Looked into this a bit to see if I could help, and wasn't able to come up with much. The coronet as part of a logo is not very unique, nor are the initials GR.
There could be some connection to King George, as BigCypressHunter mentioned. You'll find a lot of images of crowns with the initials GR, which indicated King George, but the crown is not usually designed quite like that. The crown bit does look very much like the Rolex logo, and Rolex watches do often come with "hang tags" with have some sort of insignia. GR could stand for Genuine Rolex. On the other hand, I can't find anything in vintage Rolex logos that looks anything like the logo on what you've got, and I can't find any example of Rolex using GR like that.
Looks like a keychain or luggage tag to me, but it's hard to say. Interesting find either way!