... I also wouldn't gum up / coat the spoke nipples.
Why - I can't imagine this would hurt anything - it's not like these are a service item. You're never going to tighten spokes or re-true the wheel yourself under any scenario I can imagine. And of course wire wheels made for tubeless tires have a bead of sealant similar to this run around the spoke nipples inside the rim to make them air-tight.
Only thing I would be careful of is ensuring that there is none on the section of the rim where the tire bead seats.
