The headspace issue can and will be affected by rotation of the barrel. It may be minimal however.
The barrel will need to be removed, the shoulder either roll swaged on a lathe or, if you want to P.M. Me, I'll explain how it can be done on the bench. It's really not that difficult.
The actual steel at the shoulder is quite soft when compared to hardness qualities at other locations.
My advice is to deal with your barrel first, then see where things are at with headspace before you burn cash on a bolt.