ORIGINAL: Soilarch
You can "cold blue" yourself...some get excellent results, others don't and it won't be as durable as a hot/rust blue (but you can simply reblue in a couple of years) You might look as parkerizing the barrel if you're going for a matte finish as its cheaper than having it blued.
You cannot cold blue stainless, and even most hot bluing won't work onit. The Winchester company used to iron-plate their stainless barrels on the .220 Swift and .264 Win. Mag. rifles. Then they'd blue that iron plating. It came out pretty "matte", if I recall.