I consider the background models including the wall sculpture to be canon (they were onscreen), you don't, so we agree to disagree. However, noticing your obvious interest and the time and energy you seem to invest hunting down hard-to-see background models, I can't help but wonder whether you consider these to be canon or only those you personally like?
Hmm, I thought I'd made that clear in my last post...obviously not. Well then...
This has nothing to do with what I "personally like." The wall sculptures are "canon" in the fact that they were shown on screen, but in the context of the show, the intent was that those sculptures represented all the Enterprises from the aircraft carrier all the way to the Enterprise-D, for the first few years of the show. However, once the Ambassador class was represented by the Sternbach/Jein model, the wall hanging became invalidated. At best, it then represented the previous Enterprises in more of an abstract way, as the Ent-C version now looked nothing like the studio model (just like how the Ent-B would also eventually look different from the standard Excelsior seen on the wall hanging). That's probably why they were all removed only a few years into the series.
One could also argue that, as a retcon, those wall sculptures did not in fact show the Enterprise history (even though that was the original intention), but rather instead were just sculptures of random Starfleet vessels. In that case, there could be a precedent that Starfleet indeed had a ship class that looked like that side view of Probert's design, But it wouldn't be the Ambassador class then (and yes, I'm well aware of the idea that Probert's ship could be the prototype for the Ambassador which then changed significantly in design later on, but unless that idea is canonically established, it's nothing more than a theory).