Can anyone tell me if I can fit a later year rear fender to my 2010 beta Evo 250 that has the removable air filter cover so I don’t have to keep taking the complete fender off to clean the air filter? Thanks 

I can't answer your question, but I used to remove the airbox cover screw and tape the cover semi-permanently to the guard, then use cable ties or nylon bolts at the rear fasteners so the guard could pop off without breaking. Effectively I converted my 2017 & 2020 Evo guards into ones similar to your 2010.
I found it no problem to just lift the guard and change the filter and far preferred not breaking an expense guard in crashes.

Going to a new style guard might not necessarily be an upgrade as much as a downgrade in my view.