I feel your pain. I owned a '57 Special Riviera 2dr HT. Those cars are a bitch to find parts for. Try contacting this guy, he's a Buick parts vendor that's in my area and helped me a lot. Ed Baker 5507 Barnum Rd. Akron, NY 14001 Ph# 716-542-9257 This guy is also a long time Carlisle vendor.
There is a place in Denton, Texas called CTC Auto Ranch. I have used them in the past. Friendly, knowlegable staff, and a TON of cars. Don't have the number off hand. but a google search should bring it up/
THANKS everyone for your help.Order the parts will have them friday. Lots nice people on the H.A.M.B. TwoChops