My antique cameo ring is set in gold but there is no kt stamp on the ring. The band is stamped into the gold what appears to resemble a large 3 laying on its side with the letter M in the first circle of the sideways 3 and the letter H in the second circle of the sideways 3. Who could have made this and what karat gold was used for the setting?

You could try looking here to see if it is in their list.

Basic Hallmarks Identification (http://www.modernsilver.com/basichallmarks.htm)

I found a cameo watch ring. It has Bruhrer and something like plaque orlamin somicons ? Made in Germany 17 jewels
Don't know value ?