Here is a listing that I made and have posted several times without too much disagreement from the peanut gallery ....

PSP - Early 9mm version labled PSP on slide & checkered grips. About 239 of these reportedly made before transitioning to the P7.
P7 - Labled P7 on the stippled grip with protruding heel mag release, 9mm x 19 on slide. This is also commonly referred to as the P7PSP (or mistakingly the PSP) but the slide or grip is not marked so.
P7E - Same as P7 but with flush heel mag release, labled P7E on frame and P7 on the grips. This is also commonly referred to as the P7PSP but is not marked so.
P7PSP - Last production run of the heel mag release guns in 1997, labled P7PSP on the slide and P7 on the grips. These came with a lifetime warranty unlike any of the previous heel mag release guns. Looks the same as the P7E.
P7M8 - Labled P7M8 on slide & grips with grip frame mag release behind trigger, 9mm. Also had a commemorative version of 500 guns in 2004.
P7M13 - Same as P7M8 but labled P7M13 and 13 round capacity.
P7K3 - Labled P7K3 on slide & grips, interchangeable in .22LR, .32ACP, & .380ACP calibers.
P7M10 - Labled P7M10 on the slide & grips, holds 10 rounds of .40S&W and has a taller slide.