I would like to know the age of a mandolin I have obtained.?

I was given this mandolin (could possibly be a banjo or ukulele too) by my great-aunt. It has "The Gem" stamped on the headstock, and just underneath "223". I would like to know its age, model and/or make. I can send/post a picture if necessary. It has a "Grover Nontip" bridge, and there are 4 sets of 2 strings (ie 4 double courses of strings). Any help would be great!