Well, the project is coming along.
My good friend Stephen Bottcher stopped in town for the night on his way home with a 1992 R100 in the back of his truck.
So with Stephen's help, I got the short-block removed from the frame, and then we propped up the rear of the frame and took off the center stand.
I pulled out the new replacement stand (used) and it fit right in place, although it seems to be a little taller than the other stand.
Does this additional height have anything to do with the [supposed] easier-to-heft 2nd generation bikes, do you think?
But with that R100 sitting in Stephen's truck, I was able to get some good pictures of where a "proper" bump-stop should go (sorry Bob, I am a visual person).

click for larger picture
It may not be the same on the short framed bikes, though.
And here is my first real issue:

Both sides are the same:

Stephen didn't think anything was wrong because we were able to torque them down and there is no lateral movement. Just the same - it wasn't that way with my old stand. And I got to thinking about it, and went out to the truck to check out the R100. Sure enough:

But the engine won't be arriving for another week or more, so I have plenty of time to figure it out.
There are two to choose from,:
16 Bush
11MM 2 46 52 1
236 528 $3.64
16 Bush 13,5MM 2 46 52 2 301 704 $3.86
The 11mm bushing is the only one listed in my hardcopy Aux. Catalog, which was published before the '81 models came out. And it lists the same part # 236 528.
I don't see how a 13.5mm bushing is going to solve my problem. I need shorter ones - or to find out if/where the problem truly exists.
Tomorrow I will measure the thickness of the tops of the stands.
Thanks guys.