'51-'87 (for the most part...'91 on some models).
'51 doors are one-year-only and rare. Someone here about gave me a seizure a few months ago when they said they converted a set to remove the vent windows.
If you don't care about keeping the push-button handles, just get a set of '47.2-'50 doors and change the striker plates. If you want to keep the push button handles, I'd find a set of complete but battered '47.2-'50 doors, cut the skins off, and start the conversion there.
