Contact Albion for verification on your saddles codes and information:  https://www.albionengland.co.uk/saddle-verification/

Antares

Eg. 1 17 E 09 602 
P = seat depth 
A1 = flap 
17 = seat size (generally true to size) 
E = tree width 
09 = year of manufacturing 
602 = item number of the year 

Seat depth : P is flat, SC is half-deep, C is deep 
Flap: Length goes from 00 to 5, 00 being the shortest and 2 being standard. The letter following the length number describes the forwardness of the flap; N being standard (more straight); A slightly forward, AA forward and AAA very forward. There are also specialty flaps, like AB (low advanced which is forward with a lower forward curve), NB (normal with a lower curve), D (dressage, which is a flap on a jumping saddle with a straighter cut) 
Tree width: E = narrow, N = standard, L = wide, XL = extra-wide. Sometimes : AO = Arcade Ouverte = wide tree 

Sometimes, additional info such as “M10” = a panel designation that means they’ve added 10mm (or 1 cm) of extra padding above and beyond the standard panel. 

175 = seat size (usually true to size) 
N = flap 
1234 = item number of the year 
0113 = Date of Manufacture (January 2013) 
M = tree width 
4 = panel volume 

Flaps : short = K, normal or regular = N, long = L, extra long = XL. If the flap has a forward angle, there is code “SW” added. 
Tree widths : Narrow = -1.5, Medium = M, Medium Wide = +1.5, Wide = +2.5, Extra wide = +3.5 
Panel Volume: Each saddle is made with wool flocked independant panels that can be chosen in different volumes 2 , 4 (and in Dressage Saddles 6 as well). 4 is standard. 

LHI – If you see this code in any Amerigo serial number, this means that the saddle has been made with an extended head iron. The longer head irons are suitable for horses with longer, hollow withers. 

Saddles made 2009 or after have also been stamped with a code indicating the model. Please refer to the link for the full list of codes. https://www.amerigo-saddles.com/eshop/products/50230/download/amerigo_saddle_codes.pdf

C18 2 1/4 925 07 
C= seat depth 
18 = seat size (generally they run large) 
2 1/4 = flap 
925 = item number of the year 
07 = year of manufacturing 

Seat depth : P is flat, L is half-deep, C is deep 
Flap: 1 is standard and 2 long, 3 is extra-long.  The second part describes the forwardness, 1/4 being slightly forward and 1/2 more forward. 
Tree width: E = narrow, N / S = standard, W = wide, XL = extra-wide (if not mentioned in the serial number, this means standard tree)

Depending on the age of your saddle, your serial number will either be on a sewn in tag, or stamped on the under-flap of your saddle. 

Contact Bates for information on your saddle serial number https://batessaddles.com.au/pages/contact-us 

Contact Black Country for information on your saddle serial number  http://www.blackcountrysaddles.com/contact-us/ 

CWD: SE 0217 TR 2C PL 08 4223 
SE02 = saddle model 
17 = size of the seat  
TR = seat depth 
2C = flaps 
08 = year of manufacturing (2008) 
4223 = item number of the year 

Saddle Models: all referenced here http://www.cwdsellier.com/us/en/boutique/saddle (just look at the bottom of each picture for the reference codes for each saddle) 
Seat Depth: TC is flat, TR is half-deep, XTR is deep 
Flaps: Length goes from 1 to 5, 1 being the shortest. The letter following the length number describes the angle of the flap; C being more forward while L is standard (more straight). 

There is a serial number running vertically down the upper outer edge of the sweat flap and the first two numbers of the serial number are the year of manufacture. After the serial number is a single digit number- it is the number of the saddler who made the saddle. Contact County for more info  https://www.countysaddlery.com.au/contact-us 

Eg. 17.5L63601114 M +1 
17.5 = Seat size 
L = Flap length  
6360 = Serial number 
1114 = Month and year of manufacture  
M = Panel thickness 
+1 = Gullet width  

Eg. 13 06 001 73BMR0 
13 = Year 
06 = Month  
001 = Serial number 
7 = Seat size (17) 
3 = Withers bar (33) 
B = Forward (flap)  
M = Flap size  
R = Seat  
0 = Panel  

Seat- 
16 = 6  
17 = 7 
18 = 8  
 
Withers Bar- 
29 =9 
30 = 0 
31 = 1 
32 = 2 
33 = 3  
34 = 4  
35 = 5  
36 = 6  
37 = 7  
38 = 8  

Forward-  
-2cm = D 
Standard = B 
+2cm = F 
 
Flap size- 
-8cm = Y  
-3cm for jumping, -5cm for dressage = S 
Standard = M  
+3cm for jumping, +5 for dressage = L 
=7cm for dressage = X 

Seat- 
(Dressage)  
Deep = D 
Open = A 
(Jumping)  
Standard = R  

Panel: 
Flat = Z 
Standard = 0 
+1cm = 1  
+2cm = 2  

Eg. 1 DHE 17.5 1443 12  
DHE = Model  
17.5 = Size 
1443 = Serial number  
12 = Year of manufacture 

Contact Aitkens saddlery for panel information – https://aitkenssaddlery.com/pages/contact-us 

Start by looking at the four numbers together on the saddle flap.

The first two digits are the seat size. These will be either 16, 17, or 18 for the seat size in inches.

The next two numbers in the four number block is the tree size in centimetres.

The tree of a Prestige saddle can be adjusted so if there is a number stamped underneath the second set of numbers (the tree size) that means the tree has been adjusted and the adjuster has stamped the new tree size underneath the original.

The sizes in cm can be broken up as follows:

31cm – narrow to extra narrow

32cm – on the narrower side of medium, typically a horse with good withers but a medium to narrow back, like a typical TB type horse

33cm – medium

34cm – generous medium, fits many horses well

35cm – wide

36cm – extra wide

37cm – extra extra wide

The next three digits of the serial number stamped on the saddle is a three digit serial number given to that particular saddle as an identifier of that individual saddle.

After the three digit serial number, it is followed by four more numbers which is the date of manufacture. This is set out as MM/YY.

Some saddles have another marker stamped at the end of the eleven digit serial number which tells you the tanning batch the leather came from. They are not always on there.

The final marking may be available which could be an “L.” This means that this saddle has a long flap.

Depending on the saddle it may have another letter printed towards the end. For example, an “A” means that the flap is +2 inches more forward than a standard flap and “AA” means the flap is +4 inches more forward.