Chrome lined will be adequate. Never build an AK on an untreated carbon steel barrel. I'm paying for it right now. My AKS74 clone's accuracy has opened up from a 1.5 MOA group to six or seven MOA over the course of four cases of 7n6, simply because the semi-corrosive ammo has degraded the rifling. Yeah, you can clean the everliving shit out of your AK after you shoot corrosive ammo through it, but it's an AK... in my opinion, you shouldn't have to. Conversely, my Cascadian Revolutionary War battlefield pick-up was built with spare parts (chrome lined barrel, chrome gas piston, etc), has *never* been cleaned, and has roughly 10,000 rounds of all types of fucked up 7.62x39 through it, and has literally ran flawlessly ever since I finished it. Had a trigger reset problem due to gravel in the receiver, but that obviously wasn't a problem on the rifle's side.
This right here. Buy these retaining plates, and forget shepherd's hooks ever existed.