Tim,
I have never seen the fender trims listed as an option (nor shown in a GM photo or illustration) for a Suburban. In some years, 1947-1951, the Truck Data Books even states it explicitly: "(Not available on Canopy Express models or Carryall Suburbans)".
I think the option might not have been available in 52-53 (minimal brightwork those year and no RPO-390 De Luxe Equipment was available). In 1954/55, it is not so clear - the trim pieces do not seem to be specifically mentioned in the TBD. However, the Engineering Features manual states and shows it being available only on Panel trucks.
Since just about anything might have been special ordered, I would guess that someone might have been able to special order the fender trims for a Carryall Suburban or Canopy Express.
