Roy Mazzacane wasn't the only friend of mine who was at that ceremony for Jack and Avery on '30 Rock'. But within the "reality" of the Toobworld Dynamic, he wasn't there as himself. Broc Hempel on the other hand appeared as his televersion.
Performing with his bandmates Sam Trapchack (on bass) and Christian Coleman (on drums), Broc played the keyboards at the rooftop reception. They can be seen in several shots (as pictured here) and then can be seen standing in the back of the seating area during the renewal of the vows. (And that's Roy Mazzacane as Rep. Anthony Hanley in the second row, on the aisle to the right.)
Broc and "Broadway Brassy" play the Rum House at the Edison Hotel at least once a month. And if you want to see Hempel. Trapchack.Coleman perform, they play every Sunday night at Dominie's in Astoria.
Check them out!