68 Hemi Dart's at Mecum Indy

The 270 is the lowest line Dart Hardtop.

The first thing Chrysler Engineer Bob Tarozzi did in late 1967 when beginning the design of these cars was weight analysis.

I own Bob’s 3” thick binder full of notes from the Super Stock project.

He was looking for the lightest and most optimum components to build the cars. And he got reports from departments on the weight of parts. I don’t think he has a weight for door panels listed.
But the presumption would be the lower line 270 panels weigh less. I’d guess the only difference would be the emblem; 270 smaller than GTS, but thicker.
Just playing devils advocate here. Maybe, but the doors were dipped, eventually the front fenders and hood were fiberglass. Bumpers were thinned, and they all were reportedly shipped over to Hurst with a 383. Wouldn't that require some sort of documentation that a 383 was in the 270 body or did they use 270 doors on a 383 body? The same mindset apparently didn't carry over to using the low level Barracuda.