Hallmark 30KDM

Happy Holidays!

I had a friend that received a chain for a gift and there is an odd
stamping on the clasp. The marking is the following:

30KDM

They held it against other chains they have (which are mainly 22k
from India) and it looked duller. Anybody recognize the marking?
Possible karat or manufacture stamp?

Thanks for your time… cheers… tracey