I made a post compiling the S&W and G&G fit codes from several catalogs. The same numbers were used for more than one handgun over that time.
59 (also 39) = S&W 9 mm, 10 mm, .40, .45 Auto, Colt Commander, Glock, Ruger P85/90, Star
The basic 4 inch K frame size is 34.
2 inch J frame = 62 & 72
Full list is attached as pdf -- that black square.
Link to my post:
A better Smith & Wesson Leather Co holster fit chart G&G too
And one from that other guy:
Smith & Wesson holster code & size chart