I'd say the item is fairly modern, i.e. made in the last 50 years or so. If bidding, treat it a s a decorative item and not as an investment. I had a part time antique and collectables business that I ran for about 10 years and when buying from auctions items like the one on e-bay would often turn up in mixed lots. As for the date on the back of the dish 1764, this would be a factory item number.
exact dating of porcelain is only an approximate science, especially with older pieces as collectors can only go on makers backstamps or imprints that are well documented in various specialist books.