T5 tailshaft bushing and seal questions

Hey guys, i'm about to put a T5 in my 66 and i was going to replace the tailshaft bushing and seal, but the problem is, i cant find a seal that matches the one that came off it. The flange is the right size, but the rubber dust cover thing is about 3/4 inch too long. If i were to put it on it would stick out much further than the tailshaft itself. Any thoughts? I believe this trans is out of a 91 GT, did ford change this part at all over the years?
Thanks.

ok thanks, i'll just use the one that the parts store sells. it just worried me a little when the part i bought doesnt match the part that i took off.