looking for a real fm3 demon 340 1971.

Good luck with that, FM3 (Panther Pink / Moulin Rouge) was not available at all on the Demon in both production years.
The only A bodies available in that color were the Darts and the Duster, 1970 only, extremely low production #'s.

1970 Duster Coupe; 0.7%.
1970 Duster 340; 1.9%.
1970 Dart swinger; 0.2%.
1970 Dart 340; 0.6%.

All the best,