Step sides did not have optional bed trim - Only the fleet side bed had the option. Otherwise:
Custom options included; Appearance options (432), Comfort options (433), and Chrome options (393). Look at data card for RPO numbers.
Appearance; Bright metal radiator grill, windshield molding, rear trim plates (sails), horn ring, chrome trimmed instr panel knobs, 2-tone box door and 2-tone door panels.
Comfort; Driver side arm rest, passenger sunshade, full depth seat, right door lock, insulation, chromed cigar lighter.
Chrome; Front bumper, hub caps.
Bed trim, rear bumper and other options also available.
Source; GM heritage.