I have #2754 on my MC41. It's documented authentic with a letter from Unertl Optical Company, Inc. dated 30 December 2003. It was sent back to them, inspected, cleaned checked and zeroed. They replaced the return spring which was usually removed in service and I've left it alone. It's like new. The Gent I bought it from is much more knowledgeable than I when it comes to vintage US sniping equipment and posts here from time to time as Lt1. Maybe he'll chime in if he sees this thread.