Need Help determining the Manufacturer

[Lucky 138]

So my grandmother has this 3 handle set up. When she takes a shower and turns the middle handle to adjust water flow from spout to shower head water continues to flow from spout also. When she turns all knobs off water drips from spout. Anyway I'm trying to repair this my self by replacing seals, seats, cartridges, or stems. But I cant determine the Manufacturer of this system. Took the faucet off to find a logo on the bottom but there is hard water damage and all I can make out is an oval cant make out the initials inside. Anyway here are some pics any suggestions would be greatly appreciated!

 

[Geofd]

take the stem to a plumbing supply house if no one here can identify it, and the pictures