I have a regular 69 Corvette and a Model A with a Corvette rear end. I have been running that for years with no problems. You are right about the parts you mentioned that you have to narrow. In addition, you have to weld in a special bracket for the coilovers, and a special brace and crossbar for the front of the differential.
I am not sure if all vettes have the same bolt pattern on the housing but I doubt it. If you go to ecklers.com they show rebuild kits for Corvette differentials that might give you the answer. It seems 63-79 are the same, then a change is made and 80-82 is the same, then they show another change from 84 to 96.
Some web sites that might give you a more exact answer. tci.com They specialize in frames and offer the option of the corvette rear end on a Model A frame. ncrs.org and corvetteactioncenter.com are both web sites that specialize in Corvettes only and you could post a message on there. Hope that gives you some information to investigate with.