If the method above doesn't work, the hinges are still available from GM:
http://www.gmpartsdirect.com/restora...tocategory.cfm
Click on the "restoration" tab and follow the steps from there. Just click on "show all categories" at the end and they're near the top.
I bought mine a couple years ago. They must be getting low on the LH side because they're about $25 more than the RH side. It was the same when I bought mine as well.