Well, I'm sure of two things - first that mine was one of the very earliest ones to be broken and fixed; and second, that it sure wasn't the last.
While the guy who welded it is long dead now (he died of the flu, of all things, at the age of 27) he was a pretty good welder, but Miami (where the bike was) was full of such people then, as now. I was not there when he fixed it, but it was obviouos he just chamfered the broken part and welded it back in. The bike it was in was destroyed about three years later when a hit and run driver ran over the guy I sold it to but by that time it had over 25,000 miles on the repair and it held - meaning there was no metal fatigue resulting from the localized heat sufficient to result in a later crack due to vibration. I really don't recall how much he charged me, but it was such a small amount that it wasn't memorable. I have also had cases welded on outboard engines, but never with much success on them.