1970 340 R/T cars are a grey area...There was an A66 (can't remember off the top of my head) package known as the 340 performance package available for the JH23 "Highline" price range. The cars weren't true legit R/Ts, they didn't have the JS23/JS27 VIN prefix. The reason why they were grey area cars (again depending on the amount of THC in the assembler's bloodstream), is that some of the A66 (checked the code, it is...damn I'm good!) cars had R/T striping, R/T badging, and other R/T-only goodies.
Now in 1971, you could get the A66 Non-R/T 340 Package, and a legit JS23 (remember, no R/T ragtops in '71) 340 R/T. I remember seeing a way cool 340 '71 Challenger in MCG a few years back. It was FC7 Plum Crazy, had a shaker, go wing, R/T sidestripes. First glance, I thought it was another R/T. I looked closer, and the R/T side stripes were missing the "R" and the "T". As it turns out, the car wasn't an R/T at all! You see, in 1971, you could order any 4 barrel car with a shaker! Just like the '70 sidestripes had the R/T and non-R/T stripes, the '71 Stripe were the same way. A pretty option-saavy insurance salesman specially ordered this car. It was, by all means, an R/T, with the exception of a few stampings on two metal tags...
It is my understanding if it's got the wing on the back it's an R/T
Again, my last paragraph blows that out of the water. Like I say, it doesn't take a great degree of difficulty to bolt one one. Keep in mind, anything is possible over the last 36 years.
My old Avatar was a '71 340 R/T sunroof car. I remember seeing that thing on carsinbarns.com. The story with that thing was that the floorpan was so rusty that the car literally broke in half when it was loaded on the trailer!
As far as the T/A cars are concerned, they were not R/Ts, nor were they A66 cars. The 30 or so '71s that were constructed before Dodge pulled the plug on the T/A project had the quarter panel antenna hole plugged and were converted to A66 cars.