Mark,
that seems feasible. Mine is a different type though, certainly first year RR and super flash type.
the pic below is from Mike Reillys site. Your clocks are still rubber mounted as fitted to bolt on brackets, not the plate. Whereas my clocks bolt straight to the plate, so no rubber mounting as clock studs very short.
So yes while the later bikes rubber mount the individual clocks, this early style bracket doesnt.
Mine must be transitional as has a cutaway for a steering lock, but the 54's didnt have steering locks, so perhaps the one on Mikes site is off an earlier superflash