I have two of them and have had three others. Yes the barrel is threaded for head space , their is a small pin but it is only there for alignment ,then you have two sometimes four spot welds.
These welds need to be drilled out with a flat tip drill ,not a taper tip.
Unscrewing it you need to see if it is right hand or Left hand threads ,they used both.
Having a mill would be best ,a drill press just is hard to use unless you get over 500 bucks then you may as well buy a mill.
A mill is a must ,i use it more than i do a lathe.
Your new barrel will come as a blank so you can set your head space.
spot weld the old spots in the receiver then line up your site to drill and weld it.
Man you have a rifle some guys are getting 3500 or more for.
Do not attempt this on a drill press ,a mill has a large table and exact movement for your drills.
Let me save you that pain.