I use copper antiseize o my AK Muzzle devices, when it is convenient - as in, when I'm assembling at the bench and have it right there.
My dry, desert climate, and occasional cleaning has not resulted in any seized muzzle devices, but I've had to use extreme measures to remove muzzle devices from parts kits and customer guns. Sometimes they are rusted in place.
I see no downside. So if it's convenient, I use it.
I also use it on other threaded portions of the other guns that I work on, if my disassembly of rusty parts kits shows a pattern of seized parts. So the FAL for example, I use it on the return spring plug and screw, sometimes the grip screw, and sometimes the windage screws. But there is only one threaded part on an AK that was designed to be removed by the operator, and that's the muzzle device.