I have a Waltham size 12 open face model 94 made in 1907. The case is 14k gold and there are six small diamonds set into the back. How would I sell this on Ebay? Would I have to get an appraisal from a jeweler to use as a COA for potential buyers? How do I convince potential buyers that the appraisal is not something I cooked up myself? Please help.