Bob I dug out that front bumper today and had a good look. With a bright lamp, I could make out the following, in 2 locations either side of the centre of the bumper, near the top edge:
F 1 2 M 3 0
There is a reasonable space between each character/digit, unlike the one on your bumper - would guess at 3/4", but will measure tomorrow. Tried to get photos, but iPhone had trouble focussing; will have another go tomorrow.
To avoid any confusion, this bumper isn't from my car (still has it's VE3) but I got it from a guy who put a brand new repro on during his restoration, this one has all the signs of being OE so far as I can tell.