There are some significant historical inaccuracies in the equipment at the WWII museum. For example, the F4U they have hanging up there is a -4 model, but is painted as a much earlier model. I suspect this is because they wanted to represent the earlier model, but that wasn't available to them. They aren't making a lot of F4U-1s these days, and the last one I saw for sale was $1M. That was airworthy, which commands a premium, but still. To me, that's a misrepresentation, but not my museum. There were plenty of -4s that served and it could've been painted to represent any one of those. With the Sherman, I suspect it's the same thing. Most likely, they couldn't source a proper 76mm gun. While it's a great museum, I feel like they spent a lot on A/V, and not enough on the actual artifacts and their explanations. They should have spent some time seeing how the Imperial War Museum does it. They're gold standard.
Awesome opportunity to be there for that event though.