Also, had this MSD existed by the time of the TMP production, they rather would have used this one for the screen graphics than using the stuff of Franz Joseph.
And according to the official TMP blueprints the movie Enterprise
belonged to the "Starship Class II" and the "new Enterprise Class".
I'm not aware that TNG officially established "Constitution Class" for the TOS Enterprise
I've just compiled plenty of evidence
in the "Enterprise-A" tech thread that we might be looking at a lot of confusion here.