I know this is floating around, but this one you can copy and paste it into a document for reference.

The first two digits indicate caliber-
39=9mm
59=9mm
69=9mm
10=10mm
40=.40S&W
45=.45 ACP
35=.356TSW

The third digit indicates model type-
0=standard model
1=compact
2=standard with decocking lever
3=compact with decocking lever
4=standard with double action only
5=compact with double action only
6=nonstandard barrel length
7=nonstandard length barrel with decocking lever
8=nonstandard length barrel with double action only

The fourth digit indicates type of material-
3=alum frame with stainless slide
4=alum frame with carbon slide
5=carbon frame and slide
6=stainless frame and slide
7=stainless frame with carbon slide