Unless his PC is part of a band uniform (not something he invented for himself) chevrons, patches, clan badges, band sashes, etc, on a Prince Charlie coatee (which itself should never be worn before 6PM) is in extremely questionable taste. The same would hold true for an Argyll jacket.

That said, if an entire marching band were so attired it would become a uniform, albeit just about the dumbest looking uniform one could possibly imagine. Just think of a college marching band in white tie and tails, with their school logo plastered all over it-- the effect would be the same.

But as we all know, there is no accounting for taste-- good, bad, or in a PC covered with patches!