I've just purchased a used Mac Pro that was sold to me as a "5,1" model, which according to everymac.com and Apple's support site, should be a Mid 2010 Mac Pro. However the model display in System Information/About this Mac shows it as an "Early 2009", as does the Apple warranty check.
It does have the 3.2GHz Quad Core Xeon processor which was only available with the Mid 2010 model (again, according to everymac.com) and the latest firmware for the 5,1 Mac Pro. I'm not sure if the latter is an indicator though as some searches around the web suggest that it was possible to upgrade an Early 2009 model with the 5,1 firmware which should make it a Mid 2010.
So, I'm wondering if this is just a case of Mid 2010s reporting themselves as Early 2009 Mac Pros in general, or if this model has had both an upgraded firmware and upgrade processor?