how do I find manufacture of faucets

I am buying a home and some one has taken the handles and spouts off the shower and tubs.
How do I go about identifying the maker of these faucets. The guts are still there just the handles and spouts are gone. There is no name visible on the stems.

Thank for any help,
Greg

Can you post a picture of the mixing valve?

There NEVER are identifications on the stems, and seldom on the valve bodies. A picture of the stem AND the valve MAY give us enough to identify it.