Your correct on the car being a real GTS, not a GT like I was told it was when I took it in trade back in the early 1990s. It had a GT decal on the trunk panel and 1967 Dart GT door panel with the original GTS inside door emblem removed and missing when I got that car
I learned later that Dodge did offer the 383 in the 1967 and 1968 Drat GT but not in the 1969 Dart GT Only Swingers and GTS got the 383 motors in 1969