They are 415X concave rims, according to the the '88 Bridgestone catalog on Sheldon Brown's site they are original to the bike. I'd never come across concave rims before, I can definitely see where they'd be a PITA to keep clean!

I'm going to clean it up, put tires on it from my tire stash, tune it and put it on CL and FB Marketplace early next year. If I work this right I can get enough out of it to not only get the Nishiki for free but have enough "credit" on the deal to replace all the consumables it needs and qualify it for the next Clunker Challenge with room to spare on the $100 limit. Yeah, I bought BOTH bikes THAT cheap!