I'm surprised about them doing that cause I've gotten stuff from them and I've never had a problem with them or them saying something on the website isn't correct.
Here are a couple of other places you can try:
High Performance Salvage, Inc.;
1stChevyParts.com says Chevy but they carry Firebird parts too, just use the parts catalog to find what you're looking for; Billy Graham's Camaro/Firebird, the phone number and address is: (205) 668-1169, 970 Highway 202, Calera, AL 35040 (website isn't coming up for me). You can also try local salvage/junk yards, local newpapers for anyone parting out a car or even eBay for them.