Hi, I clean a lot of recovered aircraft wreckage, when say a lot I mean a lot!!
Anyway, I would avoid evaporust on those alloy plates, I have found evaporust eats away at the fragile plates removing some of the writing, if you do use it don't leave it in for long lengths of time.
ACF 50 is a good corrosion inhibitor, it is available on ebay, I coated an object 8 years ago that was heavily corroded and it is still as sound as a pound, it's origins are from the aviation industry but is now widely used in the automotive industry. It is a purple oil that fizzes slightly when applied, it goes clear and leaves the item slightly greasy, the ACF-50 travel and creap down the intergranular corrosion killing it as it goes.
That painted number 6271 I think is likely to be the aircraft werk number which could provide you with a history - worth putting on one of the aviation forums such as the Historic page on the Flypast Forum.
Hope this helps a little.
Dan