www.925-1000.com

I'm not sure of the marks but the item itself is a Mayan calendar.

Here's a good picture of an Egyptian silver date chart that i just found on Flickr, it says x hallmark is from 1922-23

http://www.flickr.com/photos/44079982@N08/4190577772/" onclick="window.open(this.href);return false;

Also the Roman Lettering system was changed to Arabic letters after 1940 so it has to be from before then.