Replacing Generic Shockmount  

I picked up two fiberglass chairs that I'm still trying to figure out who makes them. The bottoms have 4 rubber shock mounts that whoever reinstalled used way to much epoxy and the bottom looks like a mess. The screw slots also seem to be pretty stripped as well so I want to replace the shock mounts but my question is where do I get new ones? The ones in the front seem to be standard Eames size but the ones in the back are an inch tall and have a slant to them. Any thoughts as to where I could pick them up?

If I can at least save the awkward sized ones and just replaced the Eames sized ones what do you think the best way to get all of the epoxy and what seems like silicone off without damaging the rubber? I wish I took pictures before I dropped them off at my dads but I didn't think about it till now.

Also these are worth it to restore, I spent $25 on the two and they're going to clean up nicely, just need to figure out my shock mount problem.