Hey Gary! Actually i believe you are thinking of a '69 500. The '69 500 has the rear window flush, and the grille flush as well, without the characteristic hidden headlights (all 2nd generation chargers had 4 headlights) On the '70, the roof is the same. Outside of a few factory options, there is really not much difference between that and a base model charger. On ebay, i had seem a '70 R/T resin conversion kit, but the R/T has the door scoops along with the badges. Not exactly what i was looking for.
The 69 R/T kit is pretty common these days. I suppose that if i see nothing, i may pick one up as an alternate. But, i thought i would throw that out there, hoping someone knew something i didn't. Thanks!