From my own experience, you can only obtain the peg as a replacement for the HP rearsets on a 2105.
It may be different for earlier years but I would doubt you could source spares.
I had to buy the Complete left hand side ( including the gear shift and heel guard!) when the peg snapped and damaged the face plate.
Ill be repairing the old one by tapping a larger thread into the face plate and keeping for a spare....