Stanadyne was a brand that Moen valves were sold under. The parts, including the escutcheon plate, are standard Chateau parts. You can replace the plate and handles with identical. At one time, Moen was offereing some escutcheons and handles in the Monticello style and finish options which fit the Chateau valve. I don't know if these are still available.
The basic Chateau parts are commonly available in chrome, PB, and BN.
The tub spout probably unscrew. Check the bottom near the wall to see if there is a set screw.