You looking at going concourse?
if not, I believe Scott drake and other guys make repop’s of the window cranks.
I had a set of the ones pictured above original to my car...but the plastic was all coloured and breaking off. I bought a set of repop’s plastics but they would no fit over the domes. I then bought a set of repop cranks from my local mustang shop....BUT I note that the ones I bought were attached by set screws on the side of crank.....when opening or closing, torc on the crank, in effect, twisted the crank slightly, and the set screw came loose and the crank fell off numerous times. Pissed me off to say the least.
I ended getting a oem set from a local guy (center tightening...with just the flat metal with a hole in it, that the repop buttons would fit on) who has a storage locker of 71-73 mustang parts that he has been sitting on for ~25 years here in Calgary....they weren’t cheap but Cheaper than EPay, and I gotta choose from a dozen or so sets that he had at that time.
From experience, I would highly recommend get the ones with the center screw connections as pictured above.