As long as the rear hub is sound (races aren't pitted or grooved), it shouldn't be a problem to build it to a new rim. Finding a new concave rim, on the other hand, would be more of a challenge. I don't think they make them anymore, so you're then waiting for an NOS model to show up on eBay. There's nothing special about that original wheelset, so upgrading it wouldn't be a bad idea if the bike fits and you like riding it.

Neal