I need teaching then because I've seen plenty of "05" body 71 and 72's with chrome noses - now if I'm not mistaken ... our Über admin Mister 4x4 has an 05 with a chrome snout - with a gorgeous silver sheen.
Now I believe the 351 Boss 1971 was an 02 body - which had the option of either?
the options lists for either "02" and "05" are real messy to me -- because if you were in the showroom and you said ".. i'm not going to buy it unless you stick a chrome konk" on a 429 CJ - would they refuse? ....nah! ... they'd bend over backwards to get the sale.
Actually, my bumper's chrome because my painter couldn't figure out how to apply primer to the urethane without it cracking (and I needed a bumper ASAP for a car show - so I went that way). I also don't have the lower bright trim on mine, as it was originally a no-stripe/no spoiler car. I had originally thought I wanted the stripes and spoilers, so I removed the bright trim - pieces were missing anyway - and went with the hockey stripe treatment for the rockers. After seeing just about every car our there with stripes and spoilers (whether they came that way or not), I decided to keep mine as originally ordered, but have been too chicken to install the lower bright trim (gotta punch some holes in the sheet metal to do it).
OK, so:
Urethane bumpers were standard for '71-'72 "05" (Mach 1) and optional for others. Some special packages came with urethane bumpers (Spring Specials and Sprints, for instance). Chrome bumpers were standard for all except Mach 1s and the special packages, as equipped.
Even Boss 351s had chrome bumpers, but then again, they are "02" bodies, after all.
The '73s were kind of 'stuck' with the Federally mandated 5-mph bumper, which did change the look of the nose, somewhat. The grille changed to relocate the signal lamps from under the bumper, since they were basically invisible with the bigger chunk of urethane bumper. There were only subtle differences between the Mach 1 and standard grilles (Tri-bar pony for Mach 1, pony and corral for standard).
The fenders for '73s are different than '71-'72s as a result of the different shaped bumper.
The taillights were a subtle difference as well - the '71-'72s had black paint to trim out the light bezels, whereas the '73s were left unpainted.
Rear bumpers were tucked in a little closer on '71-'72s, while '73s were spaced away about an inch along with some filler pieces for the quarter extensions.
Stripe kits were different as well. '71-'72s could have the optional hockey stripes (that were standard for the '71 Boss 351s, originally). Deluxe trim for the Mach 1s had bright trim strips dividing the body color and rocker colors - no stripes, though (you could get the car with the no stripe/bright trim, or stripes with no bright trim... unlike a lot of cars you see these days with both). '73s had the single, straight, wide stripes starting at the front marker and terminating just ahead of the rear wheel openings. The hockey stripes were optional items for all years, I believe, and I'm pretty sure there was no lower bright trim option available for the '73s.
Hood locks and TuTone hood application were primarily for Ram Air equipped cars, but could be ordered as an optional item as well (they were "together", I believe).
There were a few minor things (seat belt light on the passenger side of the dash for '73s, for instance), but otherwise - most everything else is pretty much the same from '71 thru '73.
I know I'm missing something...