It was artwork on a wall. Are you claiming the same for the B?
What about the Enterprise-B
? In ST VII we saw the B with the added-on bumpers. Was it the first ship to feature these and what was the function of these bumpers? During events in ST VII a considerable part of the bumpers were destroyed.
Did they reconstruct these or did Starfleet get new information in the meantime that these bumpers weren't such a great thing (notice that most of the Excelsior Class Starships in the 24th Century do not have these bumpers "any more"). Maybe Starfleet decided to retro-convert the B into a standard Excelsior Class Starship? For whatever reason what we see on the conference lounge wall may just be the B in her final appearance. We simply don't have enough information (or imagination) to label the sculpture of the Enterprise-B
as wrong or flawed.
That was the "prime" universe C. Its entry through the fissure triggered the alternate reality, into which it promptly it found itself. If the C was alternate reality version the whole time, it could not have re-entered the prime universe and led to Sela, etc.
That's just a conjectural assumption. "Previously" on TNG Guinan had stabbed Q's hand. And 'coincidentally' Guinan was the only one in the alternate timeline noticing something was wrong.
For all we know the whole situation could have been Q's revenge for what she did to him in "Deja Q", as Guinan is the one being put into the uncomfortable position to figure things out and persuade Captain Picard of the alternate timeline to send this Enterprise-C
back in time.
Unless we have irrefutable onscreen evidence that in the "real" TNG universe the Enterprise-C
did look like the one in the alternate timeline (e.g. dialogue, cross-section monitor display or the like), there is no reason not
to assume that the "real" Enterprise-C
looked like the one on the conference lounge's wall sculpture display.
The only thing that doesn't work, apparently, is to assume that the Enterprise-C
in the "real" universe belonged to the Ambassador Class, too.