Thanks Keith, I know of Poche and know some of his acquaintances. I do not believe he will be able to help with this specific inquiry.

R.D. - these spikes are chopped shorter. The head has been lopped off of them. I do recall seeing a video on the web some time ago where a fellow made his own 1-pdr cannon and fired chopped rail spikes with a Pyrodex charge. The effect was impressive.

UPDATE: I did locate the primary source regarding rail spikes at Carthage. Still looking for the one from Wilson's Creek.