Get yourself some Brownell's Oxpho-Blue creme. You won't be able to match the finish, but the color will be pretty close. Or, like the Major said, cover it up with an extended shroud or flash hider.
Just as a heads up: if your going to attempt removing a flash hider, I would recommend you get yourself a good 3/4" thin machinist's crowfoot socket and a long 3/8 drive breaker bar. Or a good armorer's tool and a length of pipe for a breaker bar.
Also, some high temp polymide tape for the barrel is always a good precaution against slips. I always wrap my barrels to guard against the latter, and in case I have to heat the flash hider to get it off.