Well, no, because we do have firsthand accounts from people who worked at ILM such as Bill George and Nilo Rodis, who pretty much state the opposite of what you believe.
All we learn from these interviews
is part of the production process (at which point in time?).
But we can definitely see quite a paradigm shift from the early Excelsior
prototypes with their clone trooper / Flash Gordon / Rocketeer style warp nacelles and the TOS Romulan Bird of Prey reminiscent superstructures to the final design that's definitely more late 23rd Century than those early study models, IMHO.