You make interesting points, and I’m quite certain any model company would benefit from your expertise. Let’s look at a possibility - we know that the IS-III that used to be at Aberdeen had an engine deck from another model of tank. It fit, and even though it was a museum piece I suppose it could have been made to work.
Let’s look at another example - this F-18D:
It’s got landing gear doors from at least two other planes, one of which is an A model. I know this to be true because I’m the one who removed one of the doors.
See missing bolt on strip the prevents front hinge pin from being able to slide to the rear:
So - if something like this, that must remain airworthy, can have parts from different models swapped out, I’ll posit that the same can be done on armor. Perhaps Tamiya copied a museum piece. Or - perhaps the museum piece was simply a tank that used cannibalized parts on the battlefield, like the suspension arms. In that case, the model could be more correct. It’s an interesting possibility, See this thread - it shows that a museum actually got a “mistake” right on the ISU-152: