in 1971 the Challenger R/T only came in Hardtop model. No convertibles
I believe this particular car was being sold as having a dealer installed Hemi at Claude Short Dodge here in Santa Monica (closed now).
Nevertheless, the price offered was near Hemi convertible clone value. And it was a factory delivered base Challenger with a 383 4spd and purple/white. Which is very cool and valuable in its own right, even without the Hemi.