Not sure what you mean, John, but if you are asking if mine is the only one of this type, it is not. These are uncommon shells, but not unique.
Interestingly the long shell in the post immediately above and the 3in bolt on the far left in my first picture are two of three CS Archer projectiles found by Pete George at Mechanicsville, VA. and the ones referenced in a story of his on page 73 of Dickey and George. I got them from Jack Melton a few years ago.