Yeah, the production names are useful, i've been using those. The AN/M3 term unfortunately is, i think, what has caused much of the confusion out there. Anyway, my understanding is that the production of the M3 was stopped right after the war, with only 3000 or so built. They continued production at the onset of Korea, but in the meantime no new guns were made. I've tried chasing down information on how guns were handled if a plane was dismantled etc to get an idea where those 3000 ended up, but there is very little specific info out there online.