I don't get on here much but here is what I know...
Panther Pink/Moulin Rouge was announced in a bulletin to dealers dated January 28th and it states for early February production which was only a week later. The earliest car I have in my database with FM3 on the fender tag has a February 20th SPD which is a Charger from the St. Louis plant. The first car known to be painted Panther Pink is the Challenger used at the Chicago Auto show. It has an SPD of 211. It has a 999 paint code.
I have information on three '71 Panther Pink cars, my Charger R/T and two Challengers. My car has 148 for a paint code, the two Challengers have 999 paint codes. My car was built at Lynch Road while the Challengers were built at Hamtramck. I don't have information on any other non-1970 cars although I've heard stories of several others.
Someone would have had to special order the paint, even at the beginning of the 1971 model year. There shouldn't be any '71 or newer cars that actually have FM3 on the tag.
Anyone with any information on FM3 cars is encouraged to send me details.
Nick.