I don't know about collectable Singers, very few early models perhaps, even model 12 is in plenty in relation to collectability. We do buy them regardless and make our own collection. They can generally be sold for the same amount we bougth them, maybe fetch a bit for after repair and cleanup.
Either way, it is worth repairing the bent wood case, it looks better and it always add to the value, even if not much the ways of $ it looks better. If you keep the 99K or hand it down to someone else, the repair is worth it. I would go for a touch up in stead of full refinish like you mention. The tricky bit is to get a lacquer that maches and doesn't react badly with the existing, I think the safest is to use shellac since it's probably shellac to begin with. I think some polyuretan stuff as well as others make some lacquers sort of bubble up or turn whitish if they don't go well together.
Last edited by Mickey2; 06-21-2019 at 07:07 AM.