I bought mine about 3 months ago, got it running and made sure the trans worked. Then I stripped it down and I'm spending the winter restoring it, but not to stock. It didn't come with the stock exhaust, side covers, wheels and the tank was shot. I'm in the process of fitting a cafe style seat on it, rearseats, etc. I will post a rebuild thread soon.
I'd say your plan makes sense so far. Not sure on the "rebuilt vehicle." Perhaps it was totalled and someone put the engine in a new frame or vice versa. Have you checked the VIN numbers and engine number?