In 1953 Imperial made the newly designed Pilot Survival knife for the US Navy Bureau of Aeronautics. It's design number was MIL-K-8662. These knives have been seen in surplus stores and knife shows over the years with "bent" thumb rest guards identical to the M3 knife of World War Two and also with straight guards. Which of the guards was the first type used? Trying to figure out which design was the original. Thanks
Frank
Frank