In "Mirror, Mirror" they used stock fotage of the ship from WNMHGB, but evidently it was supposed to be a replica of the series production version of the ship only they couldn't afford to redo the markings and shoot new footage. Same way as TOS-R replaced stock footage of the pilot versions of the ship throughout the series.I wonder how they found the time for a refit of the I.S.S. Enterprise during Mirror, Mirror.
More to the episode: THAT...FREAKIN'...ROCKED!!! They kept true to their word. There were no references to anything outside of "Mirror, Mirror."
This was a lot of fun. The Mirror Kirk really is an ass and it's hard to imagine this guy getting as far as he did in that universe.
I loved the little bit at the beginning where the Prime Kirk makes his pitch. Nicely done!