Sometimes the auctioneers don't really know what it is
they are selling. There are so many different types
of U.S. military knives - for this reason it makes
them interesting to study and collect.
Books are great tools to learn from, and the internet
can also provide access to many different areas of
this subject as well.
I'll post a few 'modern' ones here if you'd like to see and
compare against yours, when I have some time........ !