It's a BSA made No5 Mk1. As mentioned before, the lower fore-stock has been cut and reshaped just in front of the barrel band. It's a real No5 and not a reproduction made from a No4 Mk1. To restore it, you need to find a new lower fore-stock. No5 stock parts are hard to find though. In a pinch and if you're handy, you can use a No4 fore-stock and reshape it into a No5 fore-stock. it'll never be a collector's item due to the holes that are drilled and tapped into the receiver unfortunately. You can plug them with epoxy and paint them black to make them less obvious. Anyway, looks like a fun project. BTW, the correct metal finish is black Suncorite paint anyway.