I had thought that more of the Finnish Air Force and Finnish Aviation Museum WWII exhibits were in original paint, but after a bit more research it seems that most have been repainted. The I-16UTI at FAM, for example, only has the engine cowls in original paint. Still, in addition to the Hurri there is also the Brewster B339 wreck, and various other parts such as the Gamecock wreck and various bits of Blenheim. The 360 degree tour of the FAFM is well worth a look…

The whole WWII aeroplanes I’m aware of with original paint job in various Finnish museums are as following:

the Aero A-32,
the B-239,
the Blackburn Ripon,
the Caudron C.714,
the Hawker Hurricane,
the Polikarpov U-2,
the P-39Q and
the VL Kotka

As you said there are also many wrecks but they are not worth mentioning. The Fi-156 at Finnish Aviation Museum might carry the original olive drab paint with added civil register number.