Hi Gasram, there will be far better than me along who will value your gun but til they arrive all I can suggest to you is that pictures and a detailed description including condition of screw heads,stock,bluing,etching etc. also the number type of locking system on the underlever,sights and any extra bits like maybe plates with owners names or details and possible stampings in the stock for gunmakers who sold it,clubs owned by and just behind the trigger guard maybe a mark as to stock length and trigger tension will help them give you a more accurate valuation
If you wish to post photos you can either try following this helpful link
http://www.airgunbbs.com/showthread....s-onto-the-BBS.
or alternatively you could let someone on here host them for you either ask or if you can wait til tomorrow evening I will host them for you on your thread,all you would need to do is email suitable photographs of you gun but due to work I will not be around much until tomorrow evening.
I hope this information proves helpful to you and best of luck finding out what you wish to know
Regards Martini