"RARE" indeed!!
A few years ago there was a set from a "pilot or promo" '70 GTX on Detroit's Craigslist, I wonder if these are the same set? The numbers I have for '70 GTX show .1% of US production (7 +/- 4 cars) had them.
There's was a FT6-"dark tan metallic" w/black & charcoal leather '70 440 4bbl 4-spd Charger R/T SE I saw at the '86? NAT's that was coded for them, but they were missing. I've also seen a EV2-"hemi orange metallic" w/white interior '71 440 6bbl Charger R/T in CA with them.
I was looking for a black set for a '71 'Cuda that was supposed to have them a few years ago - Great Lakes NOS said they had a set of (green?) ones from a '70 Grand Coupe but they never materialised. There was a red 383 Challenger R/T "dealer demo" on Ebay that had them, I'll see if I can find the pics. GG's '70 Cuda book shows .1% for US spec. 'Cudas (17 +/- 8 produced)
