2015 TTR Fuel Tank (I need one!)

Hey working on a TTR125 for a customer and he needs the Fuel Tank Replaced I cannot seem to find any fuel tanks that I know will for sure fit! I am not sure if the later model fuel tank are compatible or not.  I and he are not going to spend almost $300.00 + effing dollars on a piece of plastic when I can get a used one for $100.00 bucks or less I just don't know will a TTR225 Tank fit a TTR125 or will a later model TTR125 tank fit?  Can someone out there help me out. What other bikes are compatible and or where can I get a Desert Tank worst case scenario where can I buy one?