We need to replace a 3-handle shower/tub faucet and it's turning into a much bigger deal than I thought it would. I've gone to several plumbing stores and they can't figure out what brand this one is and since different brands have different threads for attaching, I'm not sure what kind to buy for the plumber (who is coming next week) to replace them. We really don't want to replace the valves because of a tricky closet situation behind the faucets.

I'm hoping that maybe somebody here with an old house might recognize this old relic and the brand. Thanks for any help!