OK... gonna give it a shot here,
In answer to all the above questions:
Dart GT's WERE made in 1970-1971 as an Option Package (A65) on 2 door Hardtop Dart Customs (NOT on Swingers as some have commented in the mopar world). The Option Package got you the Dart GT Emblems (1969 Emblems were used on the 1970 GT's and the 1971 GT's had Dart GT Emblems of a 1 year only style). No GT Emblems on the inside Doors like the 1969 (but I added them to mine). ALL had Bucket Seats (using the 1970 340 Swinger pleat pattern on the 1970's Seats AND Door Panels and standard 1971 Dart Swinger pattern on the 1971's). Few had Consoles. You got the Dart Custom "Woodgrain" Dash treatment with a DART Custom Emblem on the Glove Box door - but sadly NO Rallye Dashes! The Rear Ends and Leaf Springs came in every combo you could get with no ryme or reason it seems. You got HD Brakes - Drum or Kelsey-Hayes Disc, power or not. All came with Power Steering. You got 340 Torsion Bars on all 1970's that I have checked so far - Slant Six or 318. Front Sway Bar sometimes. You had 2 engine choices: 225 ci 1-bbl Slant Six or 318 ci 2-bbl. You could get any Transmission except 4 speed. Oh yeah: NO Hood Scoops or Tailstripe from the FACTORY, but some added by dealerships.