rear vernier iso

A fella on another forum says he has a new rear vernier isolastic assembly and the tube that the rubber donuts are attached to has an ID that's about .080" larger than the 1/2" thru-bolt. Does anyone know if this is normal, or what the clearance should be? It's been a while since I did mine and I can't recall how tight it was.

Thanks

Saddly , Gash seamed tube is now used, Original drilled tube is no longer the norm , its just another dogs dinner.
Down to some corner cutting,no doubt!