When did LAPD and Adam 12 go to the shorter M-15 Combat Masterpiece?

I think I recall Hurst or Hogue grips on the TV guns. They tried for authenticity. The shotguns were Ithaca M-37, like the real cops there had.

I think the holsters may also have changed. I'll try to find some episodes. I used to watch that show faithfully when it was new.

I'll look up when it ran but think it was ca. 1968-1975. ??