And I say clean, dry threads; new short bolts
absolutely (it is his first time in there), no split ring washers, and no locktite.

Only
you can decide which you want to do. Â (Gotta have choices, right?)
And I've never checked the torque value when tightening them, as I've always used the foot on the brake and give it all you got with the 12-point box wrench from the tool kit method.
I've never had one come loose on me. Â And this is one place on the bike you don't have to worry about striping threads - steel into steel.
I just bought four bolts from Hucky's. Â I think he is down your way.
http://www.bmwhucky.com/007526.html  Good, fast service.
26 11 1 242 297  driveshaft bolt M8x1x13mm  1981 on  $ 1.90

A lot of modern BMW dealers might carry these as well, like they do oil filters, I suspect.