I have put together a 12g lefever nitro from a basket case gun shop find and have discovered that I must be missing some hardware that holds the return spring for the barrel locking lever. I do have the spring, Can someone Please show me a drawing or schematic of the missing piece. If someone would have this part for sale that would be better yet. I have an old repro of a parts list and dont see a part for that hole in the first pic which engages the barrel lock. Thank You!