Question about converting CMYK to spot color

Hi fellow PrintPlaneters.

I have a question. I received a 4-color logo from a client and although I can fake it by making it any spot color I want, how can I figure out what spot color it is from its CMYK coordinates? Anybody have a reverse converter?

In this case, the logo is C51/M53/Y78/K35.

Please let me know and where to find it if it's an internet thing.

Thanks!
Cathie