Hello swede!
It's really not that shiny in real life so a Flat grey is fine....especially in scale....its always a good idea to tone down gloss finishes in smaller scales to keep models from looking toy like.
Take a look at my Hueys...those are flat tones for the Sound proofing.
http://troysmodels.homestead.com
GOOD LUCK!
Straighten up and fly right.....