65 Barracuda 187 code!!!

Where do i find out what year this transmission is? And no i dont have reverse lights haha. Whats interesting is i hear a slight buzz coming from the actual shifter when going into reverse. Its so faint i might be mistaking it for an electrical noise though and its only when going into reverse. Could this also have something to do with reverse lights? Maybe sending a signal to the lights but nothing is hooked up so it just buzzes?