I don't know if Jared needs the armrest bases for a convertible or hardtop which use a 14" long base. The post cars use a different, shorter style of armrest/base.
I was able to find a really good set in a salvage yard from a 4 door Skylark with the Deluxe interior. The rear armrest bases are the same as the front. However, the pads have an ash tray embedded into them. Like Chris said, try flipping them upside down a put the left side on the right side and vice versa.
Mr G's Enterprises can repair and plastic re-chrome your old ones. Sometimes they have the 14" long bases on hand or will swap with your old ones. Here's the link. For some reason when I try to go to the page with our Buicks info, the page is corrupted. I'd give them a call for pricing, etc. If you need the 14" long, 1965 Buick Skylark bases with the Deluxe interior, let them know exactly what you need.
http://www.mrgusa.com/John