About the XM9 unnumbered (before last photo) :
- They are extra pieces that Phrobis made but didn't submit for trials.
I don't think anyone really knows the exact number made. (Bill Porter)

- This is one of the XM9 overruns made by Phrobis for the Army trials.
Although they were required to provide 55 examples for testing, some few additional XM9s (quantity unknown) were made.
These could have been designated as replacement bayonets for the trials process, metallurgical testing & evaluation. Well, perhaps "overrun" is a bit too vague. Although the total number of Phrobis XM9s produced may be unknown, there were more than the actual number of 55 required by the U.S. Army for competition. Of that lot, 55 bayonets were randomly boxed up & shipped, leaving a small number behind. The only difference between these would be the "A" prefixed serial number, ranging from "001" to "055", found either scribed or painted on both bayonet & scabbard by the Army.
This indicates the bayonet was one actually submitted for trials competition. (PWCOSOL)