Thanks all for the info and advice. The headlight mounting holes on my reproduction shrouds are indeed "wrong" (thanks for that observation Swarfy, I had not noticed), but all the dimensions are correct - 15" overall length, 7" from the bolt center to the top of the shroud, and 7" between ears. I suppose I will have to disassemble the yokes and take a closer look at the new bearings. It seems like everything on this project is two steps forward and one step back...
Burton's and Draganfly are the only shops I can find that carry shrouds with the correct round headlight holes, but both are currently out of stock.