I picked up this Gruen autowind that the seller said was solid gold. It's marked on the case back GRUEN 14K GOLD With a J and an arrow. When I took the movement out there were no markings inside the case. I found this identical watch on ebay and it has all the correct marking inside the case. Is mine solid gold or not? I need some advice on this because if it was misrepresented I will have to contact the seller to get a refund.