well off the top of my head, the model 15 in .38 special was offered in 2in., 4 in. ( the basic main version) some in 6 in. and very few in the mid late 80s in 8 3/8 inch,,,,most of them were blued finish a few in nickel till about 1987, all the ones I ever saw were K framed ( medium frame) square butt grips, and came with 'magna ,square flat bottom
grips,,, the police, military version had a service grip, the bottom sides of the grip panels were rounded,,,made for less wear on the inside of an officers uniform jacket....they all came with an adjustable rear sight............
any more info may be found of the 9 different manufacturing changes in the "S&W Standard Catalog by Supica and Nahas, I did contribute info and photos for their Volume 3 and Volume 4 books...good book to have handy 8) :roll: :wink:
PS if you are going to collect them the valueable one is marked USAF...premium attached to that version, hard to find,... this was the sidearm of the Air Police.