hi, i'm new to the forum but i'm after some help and advice. I have a Winchester 12 bore o/u i cant find any model details on it all it has is Winchester and a serial number. i think its a 6400, can anyone let me know how to find out and what the value is please ive been to a local dealer but they wasn't very helpful and didn't offer much. Don't think they liked the idea of me wanting to sell it privately. Any help or advice would be much appreciated cheers