I can only relate what I did. 1978 Schwinn Superior. Corroded spokes, Zn plated as fietsbob pointed out. I replaced them with SS spokes of similar geometry. I was pleased because the visual corrosion was gone, I got a change to polish the hubs and rims w/o the spokes installed and I got a change to practice wheelbuilding.

YMMV. Your goals may be different.

Regarding weakening the spoke, yeah, corrosion does that. But there's some safety margin left on the spoke if the corrosion isn't too bad. I think that my wheels would have been fine with steel wool to take off the corrosion, but I wanted a cleaner look. Also, at 240lb, I figured my safety margin was lower than for the 150 person the bike was probably designed for...