The major exception, right now, to referencing later versions of the ship is the glow on the warp grilles...and I may eliminate that. One of the Loos construction photos looks as if there may have been a reflective Mylar surface applied to them.
Might that reflective tape have been intended as a lighting trick? Reflective materials were used a lot back then to light up surfaces by reflecting light from a lamp near the camera back into the camera. It's the same trick they used for the Millennium Falcon's
engines. Or the Kryptonian wardrobe from Superman
Back in 1978, someone might have thought it was a cheap and easy way to light up the warp engines on the Enterprise