I really do not want it back, kind as your offers are. As of last Thursday, my weight has dropped 23 kilos since May 20th. I have been highly motivated.
Back to plugging holes - if welding is not involved, here is how I do it:
Countersink the hole slightly. Screw in a longer than necessary screw, firmly, cut it off proud of the surface. It is even better if the portion left to rivet is not threaded. I will grind the screw flat leaving enough metal to rivet down nicely. Use the polished round end of a small ballpein hammer, and working around and around, rivet the screw into the chamfer. There must be enough metal to leave a slight hump. With a fine file, dress the rivet to contour. With fine abrasive, polish it, and just a bit of the surrounding base metal. Touch up the finish. You might need to experiment to blend the repair. The steel in the screw is important, if the alloy is very different from the receiver, the dot will show a different colour. You might want to experiment before doing the job. Might be worth making the screw, if necessary. Done carefully, a faint circle will show on careful examination.
An expertly done welded repair will be invisible, but more refinishing will be necessary.
By all means, practice on scrap metal a few times, before trying the repair on a rifle.