Right.. good luck with your gun Sig's are awesome I have one. The Sig body is usually painted dark grey, make sure you get a flat spray paint anything gloss looks funny and can give away your position.
Edit: lots of people paint their gun even if it isn't clear. Check out this thread http://www.airsoftcanada.com/showthr...ight=paint+gun
See google and youtube re: How to paint your gun.