De Ville real or fake?

Good day, I am new to the forum and am trying to sell an Omega De Ville Symbol but a potential buyer has said it is a fake. I bought in on eBay about 3 yrs ago but now my gold Eterna has been fixed it is surplus to requirements. The serial number is: 54 922 021 and there are a couple of other numbers on it: 196 0316 and 396 1016. Is it real and what would a good sale price be? Thank you. Xylophone

Well my old Nokia flip phone won't take pics so I asked a photographer friend to take a couple for me, and also included the pic from when I bought it!! I have included the serial numbers so perhaps that will help??

Many thanks JiminOz, much appreciated. I think one of the problems is that I now live in Phuket (Thailand) and places like this are associated with copies/rip-offs. I'm not that good with websites and things, and I did try to list it on eBay, but the process of listing it and sending it was far too complicated for me I'm afraid, so I advertised it locally and got the "it is fake" response. So I will have to rethink what I do with it. I was thinking of selling it for US$500.

On a completely different note, somewhere on here when I was searching through, I noticed that an Eterna watch was mentioned, and I have one which I bought back in the 1980s and it's a solid gold very slim quartz watch with an unusual shape, however I've never been able to find anything like it on the Internet, even though I have a serial number. Is there a thread here somewhere upon which I can enquire as to its worth or even its name? Many thanks again.