Appraisals is the section of the forums for asking valuations.
As for details; it depends if it's a real one or clone... obviously a real one is worth a decent price if it works etc and a clone is fairly worthless comparatively. Other than that it's a small holographic sight or a copy of. ? Clones are from £20 brand new....
EOT's usually have labeling on the bottom. Also if you look through the sight when it's on, can you see the projecting light at the bottom? If you can see it then it's a clone.