Give this guy a call. If he doesn't have the parts you need, He might be able to point you in the right direction. Got this from a few other older posts.
David Hemenway
6217 South Poplar St.
Englewood, CO 80111
ph# 303-770-5579
"Just wanted to give a plug for a source of seals for the factory crank-open sunroofs on A-bodies. I have a '75 Duster that I searched for over 3 years to find a set of ready-to-go seals for its sunroof. Someone on one of my many Internet inquiries finally sent back an address and name he had bought from several years ago and liked what he bought. I called the number given and the guy is still doing it, and I was very satisfied with what I got, and I have his permission to pass on his info. His name is David Hemenway, his phone number is 303-770-5579, he lives in Englewood, CO. If you've tried all the usual sources of seals for the crank-open sunroof, you know they're impossible to find."