Availability has changed a lot in just the last few years. 5-6 year ago I would make 10-12 trips a year to the local pick and pulls (I have 4 within an hour of me) to pull parts from donor Mopars. A’s, C’s, and FMJ cars mostly, an occasional B/R body (76-79). I’ve pulled 8 3/4’s, several disk conversions, my whole fold down seat conversion for my Duster, even a whole ‘71 Dart front clip. But in the last 2-3 years I’ve probably only gone once or twice a year, and not for any A-bodies at all. It’s not totally impossible to find that stuff, but you can’t just head down to the yard whenever you want and find what you need.