Glad you re-kindled this thread, as I'll be dropping a new block in shortly and had more mount questions myself. The thick rubber mount set one of our FGF friends here sold me afew months back are identical, no difference, and are marked with the same part number. I had always thought one was slightly different from the other.
In either case, I kept all the original mount pieces that came out when I pulled the engine earlier this month and took plenty of pics.
When I get to the point where I'm reinstalling, I'll post how it goes here.
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?