Of course, the NIF didn't exist back in 1979. It's only been operating since 2009. Perhaps if it had been operating in 1979, it would have been the obvious choice to some, then, too.
Except that the TMP sets were built for the abortive Phase II
TV revival, so engineering would've had to be a studio set that could be used on a weekly basis.
I seem to remember that the warp core was a bit different before they decided on a movie.
Yeah, that's what I thought, too.
The production tests shown here
seem to resemble the concept art shown here
more than what finally came out in TMP.
From what I understand, most Phase II sets on Stage 9 were redressed for TMP, but I don't know the details.