gruen guild

i found a gruen guild clock in my grandmother attic. its a wooden/ glass outter box with the clock inside. its gold with roman numerals and triangles where numbers should go. the clock does not work. i havent tried to mess with it to get it working it may just be dusty.  on the clock in the center on one side(left) in tiny print it says fifteen 15 and under that jewels VXN. exactly what it says and on the other side (right) it says switzerland and under that unadjusted. the picture below it was my clock looks like exactly. i was wondering how mach these were going for i have heard alot of different rumors.