My boots are Sidi's and only have 1 metal screw on inside of heel guard, which is slightly recessed. It is very possible this is the cause but it only is on shifter side. The brake heel guard on bike is fine, no visible wear...At this point my only option to completely fix the issue is to replace rearset and cover the screw area on my boot...Hmm. I have zero wear on my rearsets after 19k miles. I don't have any boots with metal parts though. Maybe that's it?
Ah OK thanks for the info .The rubber pegs were an option and also part of the touring pack.
Some aftermarket suppliers, such as Puig (I have these), also make them.