I've been going through the rest of the bike now that the engine is sorted. Making some progress in cleaning stuff up.
Not so great news in the form of lots of metal fragments stuck to the magnet when I drained the transmission oil. I didn't take a picture, but it was more crap than I'd like to see. Nothing big or or chunky, mostly dust like with thin flakes. Probably the gear faces.
The final drive was worse. Way worse. Big chunks of metal came out, including something rather significant. This really should be rebuilt, but not by me.
It appears Uncle Ben was not too up on maintenance. The engine, trans,final drive and tires all showed signs of lack of attention. I expect this bike was just never serviced and ridden hard.