help wanted

I while back, my mechanic caught the driver side door backing my 1969 2dr out of the garage ending up in picrel. I've found some 1967 doors but I don't know if they fit. been looking for a replacement door for a while and getting desperate

I'm about to take apart the rear differential of my '66 Q code (428 CID) Thunderbird, but I want to drive it while I still line up the parts I need for the rebuild. There is no code tag on the differential, so I'm left wondering what's actually in there. All I know from the door code is gear...