Yes it is, and a SRO is an Operator. We will go out on rounds or jobs with NEOs and provide a peer check if needed, in addition to performing Reactivity Management peer checks when we are the RM SRO. We are also known to go turn on a valve, operate a breaker, and hang/verify red tags from time to time. We don't want any errors and do what we can to reduce the chance for mistakes.
I will agree with you that it is ok for an SRO to do that IF he isn't in a supervisory role and there is no one else available.
If he is signed in as unit supervisor, or reactivity management supervisor, then he should not be peer checking.
I think SOER 10-2 and 07-1 are pretty explicit in this, and they specifically talk about supervisors stepping out of their supervisor role in many industry events.
My license specifically says I can operate the controls, and in fact, when I first got on crew I did some ro duties including standing ro during requal until the crews we're realigned.
However, our primary function is oversight and if we are in that role, peer checking causes us to step out of that role, and we're asking for trouble.
Think about how you'd explain to the nrc how the supervisor was peer checking the evolution he was supervising when it went wrong. I don't think that would go to well.
Justin