I believe the Marsden-type locknut is original equipment, so the pivot bolts could be left loose enough for belt adjustments to be made without loosening the lower hardware, but it's been a LONG time since I've worked on anything with the factory setup still intact. If you use stainless fasteners be sure to lube them with something designed to prevent galling of the threads. Dry stainless bolts and nuts have a tendency to pressure-weld themselves together and be impossible to disassemble.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!