Any special treatment of the exposed bare metal? Rifle is parkerized.

I use a suppressor to protect mine. Works great.

Scot,
No disrespect meant, how would barrel steel be any different from any other steel as far as protecting it from rust? How would you protect steel on anything you own from rust?

No, run it.

If you share suppressors you can get thread protectors from Amazon pretty cheap.

Yes but just a few drops of oil, some sort of grease, spray paint the threads?

I have used wilson combats grease on my end caps as I direct thread everything. Coming out of Morgans shop you do not have to worry about shavings and the machining process from what I found.

Oil, a very thin film is all you need. I wouldn't be as concerned with it. If you were to paint it, threading on/off would remove the paint.

Just do like you would any other steel, a few drops of oil, a little grease, whatever. Paint on threads is never a good idea, it’s quite the opposite.

If stored a long time, paint would be the longest lasting. Then grease, then oil.

Before using it, I would acetone off the paint. I would degrease if oil or grease was applied. Personally, I like the thread's dry. Carbon can lock the suppressor on a bit. I've never had one locked on so bad I couldn't get it off. A suppressor coming loose will absolutely affect barrel harmonics.

I have never used anything but Hornady One Shot cleaner. Knocks off some of the carbon and doesn’t leave oily residue. I don’t try to get the threads shiny clean just enough to prevent buildup. That’s just me ....never really thought too much about it. Now carbon in the barrel is another whole subject that since I got a Bore Scope has been on my mind.

I had him make a couple of end caps for mine rifles. A drop of oil, screw them in and forget it.

I don't know if this the "best" way, but it's worked for the last 20 yrs on my threaded barrels. I just use a bit of nickel anti-seize, it coats EVERY part of the tread (and anything else in the area), No issues with rust and no issues with the cans or thread protectors sticking either. Just degrease the treads before applying for the first time.