I found what I believe to be a Lend Lease 1917 in a local gun shop. An Eddystone and has British proofs on the left side of the receiver, the stock has a brass medallion with some numbers on it embedded in the stock apx. 3" from the butt plate on the right side. It also has a brass grenade site mount with graduations (in degrees?) on the left side of the forend embedded in the stock. The stock itself has no marks that I could see and is very dark with no cracks, the metal finish is mostly gone, the barrel is frosty, but no rust that I could see; overall the rifle is sound and shootable by visual inspection (would need to headspace it before I fired it). Last thing, it's marked ".303 British". They want $399 for it and I could probably offer $350 and take it, is it worth it? How rare are they?
All advise will be greatly appreciated, TIA.