Griffon,
For the most part you have a fairly straight rifle and I am assuming the bore is good. The only visible issues are the extra sling swivel up front and the bent aperture insert (might be the photo). I would want to remove the swivel and then there would be a visible plug. It can be done well but will always be visible. As far as value, don't be offended, it is worth what someone will pay. Not a dime more or a dime less. You can get values from everyone here in the end what will someone pay. Set your minimum and the market will set the current value.
