The cabs to be sold as take off units or removed from a tractor are a rare piece for sure. I have looked for them and they are quite difficult to find. Also, the after market cabs are more of a "bolt on" unit, where the Mauser cab integrates much of the tractor into the cab structure, so they aren't practical to bolt on and take off, like the after market cabs units are.
The Mauser cab is designed and intended to be left on the tractor and one removes tne doors and can also easily remove the front and rear glass, but you leave the cab shell as its the ROPS unit as well. You don't take the entire Mauser cab on and off seasonally, as its quite an involved process.
The other thing to be aware of is if you do find a cab and its missing any parts or some of the parts are damaged, the price for the replacement parts is extremely high. The parts are unique and specific to the cab. The glass is all radiused to fit to the cab and none of the panels are basic "flat glass". The Mauser cab is built much like the OEM auto companies build their vehicles, they use parts which are very purpose designed and built and it makes the cab appear and function very well.
While the Mauser cab on the 1025r and the 2025r share some components, many are unique to the specific model. I have seen more after market cabs for the Generation 1 2025r for sale than I see Mauser cabs for the Gen 2 2025r. While both are Deere models 2025r, the two tractors are vastly different and the cabs are unique to each Generational built machine.
For example, the cab door panels each sell for over $1,400 per glass door panel, the roof mounted heater is $800+, things like the latches and hinges and even the small parts add up very quickly at $40 to $95+ each piece..so carefully look over any cabs you find and make sure to check on the cost for any missing or damaged parts you are going to need to complete the install for the cab you find..........so the parts needed to complete the cab install don't end up costing a small fortune themselves.