It's not unacceptable, but it's not simple, that's the problem.
When terms are used in a specific context such as S&W collecting or discussion, terms can have more specific meaning preciseness than their generic dictionary meaning.
For example newbies soon learn that 5 screw doesn't just mean the gun has 5 screws, because there's more screws than that on a S&W revolver, which also has a grip screw, a mainspring tension screw, and sight screws on target models. As we know, the S&W specific screw count relates to the side plate and trigger guard screws on K and N frames (6 screw count on post war I frames because the mainspring tension screw is also deleted) because the screw count relates to the deletions of some of those screws which help to describe specific evolutionary model changes.
So for the Pre model term to impart it's full usefulness, its precise (specific to S&W) meaning must be understood to mean immediate pre model number guns with the same engineering design. Otherwise it's generic dictionary meaning could apply to 60 years of revolvers preceding model number stamped revolvers. And we do see "pre model" applied to pre war models on this forum. Then its usefulness for describing a specific version of revolver is completely meaningless.
So any specialized term requires understanding of it's meaning by the user for the term to be helpful. Therefore all I'm saying is, it's fine to use it, but if you have to go thru a Q&A discussion when someone uses the term in the generic way, what good is the term?