Sounds like a great car and if you could provide the fender tag info and a pic that would be great. I'm trying to keep track of all 1973 Duster340 and Dart Sport340 sunroof cars that are still in existence.
Not counting yours I have accounted for (3) Dart Sports and (7) Dusters so far. I'm sure there is a few more but not many left.
The 1972 canvas top sunroof A-body cars are very rare as that option wasn't real popular either. Strange thing also it cost twice as much as the manual crank sunroof option.
Here's some pics of my 1973 Duster340-4spd SpaceDuster :toothy7: