Hi Michael,
Sorry, but I have to disagree with you on this one.
Most, if not all ac paint had a sealer either mixed in with it or was applied afterwards over the top. Yes, after use it did matt down but it always still had some residual sheen (subtle sheen or subtilen glanz) on it. As shown with late war german paint quality, which reduced greatly, and even became water based at the end, even then the metal underneath would add a sheen through to the surface paint.
The Brits thought that true matt black on night fighters would be harder to see at night. This was proved to be incorrect, and it also took some 20mph (32Kph) off the top speed, so they reverted back to standard paint types. This is why truely matt paint was never used by any airforce (the shine also protects the paint, so lasts longer).
Yes, wear on paint may matt it down, but oil, petrol, hydraulic and brake fluids on paint and then being wipped off would shine the surface. If you look at an old car that has not been re-painted and has gone matt, in bright light or sunshine, it still has a sheen to it, in german, 'subtilen glanz'.
It is one of my great frustrations that people either produce or convert an ac and believe they are doing it justice by making it matt or forgetting to add a touch of shine, it is not realistic at all. In the model world it would be described as not being 'scale' ie not realistic.
These two pics are of the WoP Fw190D9 in CFS2. The first pic is of a matt painted aircraft, the second is of a lightly shined ac. Personally I think that the subtle areas of highlighted shine or sheen, bring the ac to life and make it look more realistic in the sim. Also here are a load of photos showing shine and sheen on german, japanese and british ac. I agree, bright shiney WWII ac are very rare, but lightly shined with a subtle sheen is a must.
Cheers Shessi
P.S Brian, and yes the GC He11 does shine up well...