One on the right looks like the one fitted to the 500/550 bank of carbs.
The one on the left TBH looks exactly like the ones fitted to the R/H switchgear of the 500 and 750 for holding the throttle open.
I might have an old one lying around, they were originally chromed but it's mostly wore off now, can you measure it, it's a 5mm screw but how long from under the head to the end of the threads.