I had a yellow 70 or 71 Hemi Challenger convertible model for awhile.
That was almost certainly the AMT kit. When it comes to Challengers, I think there are only four kits, with several variants and reissues.
1 - The AMT kit, which was simultaneously released as a convertible with a shaker and a hardtop (same body, you had to glue the top on) with the RT hood.
2 - the monogram kit, which has pretty much always been a TA (and was the basis for the AAR)
3 - The 71 kit, which was never reissued (which is why it's both rare and not very accurate)
4 - The Palmer kit. This is the one with opening doors which is set up for anelectric motor. It's very inaccurate (the Challenger emblems on the quarters run about one third of the quarter length, and a lot of the body lines look wrong).