Some time back I gave you the contact of where to buy a new sidestand lug. I am sure you must be able to get one in the US.
I would not think that the frame tube has any reinforcing inside where the lug is welded on. Someone will correct me if I'm wrong here.
I recently "converted" a 1969 frame to 1971 -1974 type myself.
It was no big deal. Replaced the cross piece under the engine where the centre stand used to mount. Welded a new 1971 & on sidestand lug.
Drilled a coupla holes in the gearbox mount to use a later type centre stand & there you go, instant later model setup.
I also drilled the holes to mount the 1972 Oil Filter setup. The hardest thing about it all is accurately marking where the holes have to be. Also you need to get the "angle" x 2 right for the sidestand lug. I just "tacked" it in place, tried the sidestand with spring attached & voila !!
The other thing I had to change were the yoke stops as I have 1971 fork yokes. The pump lugs I left on, you never know, someone may want to change it back one day. Some other holes for wiring etc were a little different but nothing mattered there muchly.
That frame has since been powdercoated & ridden around, no problem.
Only nuts like us at the forum would know any difference.
Can u weld ? Just do it. You won't be looking for a wall anymore :idea:
If you are carefull, you may not have to take the engine out !!
Disconnect the battery etc.