Markings on key pendant

[Phate008]

I have been trying to identify this key and its bugging me now bc I am at a standstill. From what I can read I see 'sterling' either '925' or '975'. The initials M.R. and a name that looks like it begins with Go or Co. If you save the pictures I have and open them on your computer you can zoom in a lot more and see the letters very closely. Even still though it is very difficult to read so I figured I would see if anyone knew from experience. Any help is appreciated. Thanks

Pics-

[sljudson]

IMO it could be Melicio Rodriguez and the mystery word read upside down may be Mexico or Taxco.
Happy hunting!

Sherri