I need the long plastic piece that goes across the two windshield locks. For that matter, I need another plastic piece that surrounds the auto shifter. Can I get that from GM too?

I just got this car, and I'm trying to get it together.

 

The first piece you described, which covers the windshield header area won't be available from the dealer. It will only be found "used" from an auto parts dismantler or on eBay. Yes it is a 'vert only part, so if you do find one expect it to be priced as if it were gold plated. So far no manufacturer has stepped up to the plate to make new reproduction pieces. Also to make matters worse there are at least 3 versions of that piece that were used by ASC through their production run. The latter piece surrounding the auto shift is available from the dealer or Classic Industries. Good luck with the restoration efforts. Lon

 

Check with Hank at Paradise Automotive--813 920-7544. he bought most, if not all, of the leftover ASC parts stock inclusing tops.

 

A few years back I priced that part, over $300 from the dealer when it was available! Mine is cracked around several of the screw holes. So I've gotten used to looking at my top without that plastic piece in place

 

FYI, to confirm what I wrote before, I ran the p/n's for those plastic header trim pieces (and many more) through gmpartsdirect.com. They all came back as not available. I was surprise to discover the 1990 complete convertible top frame shows as a good p/n (12502366). The price blew me away. I'm glad I don't have to replace mine.