Your pump is a Gilbert & Barker T177, made around 1925. As far as value, when a pump has been restored, it is very difficult to place a value on it because of the vast differences in quality of restorations. This is very hard to see in a picture. When it comes right down to it, the pump is worth exactly what you can get the next buyer to pay for it! In good original, unrestored condition, this pump will bring between $1600 and $2000 if complete.