Shiny restaurations?

Hi all,

I have been wondering about this for a long time.

Why are warbirds, which originally had a matt or dull paintjob (almost)
always very shiny when restored??

A lot of money and effort is put in to restore it to original and flying
condition and then they put on a non original gloss finish!
I can probably understand this for flying examples, glossy is easier to
keep clean,

But, I was watching a program on Discovery about breaking the sound barier.
And the original Bell X-1 was a matt orange and is now exhibited repainted
in a high gloss, though it will (probably) never fly again.

Any one?

TIA and cheers,

Dennis