If they ain't split, they ain't ****
I have one rim that is riveted and was manufactured in August of 1977. My oldest welded rim was manufactured in November of 1983. The rest of my rims are 1984, 1986 and 1988, which are all welded.
I actually just had my head rebuilt by a machine shop that has extensive experience with cruisers, and he's the one who shared that technique with me. I didn't get to do it as it was included in the rebuild.
Galley Plug
I've been told you can simply punch the plug into the head bolt hole (be sure to stuff a paper towel or piece of rag into bolt hole like OP)
and tap for 1/16" plug.
NO DRILLING REQUIRED!!!
Hey you! You know who you are. The guy with the Aussie mirror pads!
Willing to pay you TOP Dollar for a pair of new/used rubber mounting pads for 60 series OEM Toyota Aussie mirrors.