sweat joint question regarding shutoffs

[pbc]

I'm installing the sink and toilet in my bathroom rebuild and am wondering, when sweating a shut off to the copper feed pipe(s), should I disassemble the shut off? I'm concerned about hurting seals and non metal parts inside the shutoff

[HayZee518]

its always better to dis-assemble the valves. the packing on the movable part is neoprene or plastic and could get deformed.

[Redwood]

I usually just sweat then on in the open position.
However, Lower skill levels mean less heat control and a good chance of overheating.
I'd remove the innards if I were you just to be safe.