Yeah I believe in the early script drafts, Excelsior was supposed to improvise and fire the tracking torpedo, but this was switched in a revision. Either the Director or Shatner felt that there should be more emphasis on the Enterprise and Kirk/Spock/McCoy during the Battle of Khitomer finale.
I'd guess Spock's lines were originally Valtane's and Uhura's were originally Rand's, and they weren't fully checked for continuity when switched.
That said, the scene works perfectly well without that line from Uhura. You can even keep her follow-up line, "thing's gotta have a tailpipe". I am surprised it wasn't deleted or modified in the Director's Cut.