^^^You're referring to the TRX style wheels, but they were used in the 80's. This 630 should have standard 14" alloys AFAIK.
The 630 was produced from '75-'79, and was not fuel injected; that's how old you're talking. Gonna be pretty tough and expensive to restore. The rust on the door is common, due to clogging of the door drains. Also, worn camshafts are a common occurence with the M30 engine.
The e24 is my all-time favorite Bimmer, but I've refrained from getting one because of the cost of restoration and maintenance. It's really up to you, but I'd recommend you pass up the 630's and 633's and find a 635 from the 80's.