Help with Hallmarks Identification on 14k Gold Cigarette Case!!

Can anyone please please help me identify the makers mark on this 14k gold cigarette case? Ive searched and searched to no avail! The inside flap is marked 14k then the number 300 (?) and then what looks like the letters GRNO inside what appears to be maybe a large letter C or it could be a partial oval with some of it rubbed/worn off. The R looks a little shorter compared to the other letters so it may in fact be the letter P or maybe even a D. (Update: These "letters" may not be letters at all and in fact be symbols as the 2nd character almost looks like a crown symbol.)Again, I have searched and searched and come up empty handed every time! Any information as far as makers mark, possible age & value, what the number 300 could stand for, just anything that may shed some light on this lovely little collectible would be greatly appreciated! Thank you! :)