vintage original case

Got the bug to find a nice vintage automatic and found this along the way instead. It is a stainless Gruen 17j manual with date. It came with box and an unusual band. Attached to the band is a tag with Gruen printed in red with a handwritten "cx xx" on one side and 27505 printed on the other...

Hi there, I have a vintage ladies Bucherer watch that I cant seem to get any information on, i've contacted Bucherer and they dont have anything on watches over 20 years old. I'm just trying to find out information like: Age Is the casing gold or gold plated Approx. value