Gun mounts; Guns; Sights, namely, open sights for use on firearms; Sights, other than telescopic sights, for artillery; Sights, other than telescopic sights, for firearms; BB guns; Firearm attachments, namely, mounts for attaching gun sights to a firearm; Machine guns and parts thereof; Non-telescopic gun sights for firearms; Protective lens covers for non-telescopic gun sights