In my 35+ years of doing "extra-close examination" of shells, I've seen several 6-pdr. and 12-pdr. Bormann shells whose moldseam touches the fuzehole. I call that orientation of the moldseam a Longitudinal moldseam. On every such occasion, the Bormann fuze in them was the 1850s form (having two separate square wrench-holes). Therefore, I think the odds strongly favor your Selma specimen's iron body was manufactured in the 1850s ...regardless of the form of the Bormann fuze in it.
I've also seen a number of "longitudinal moldseam" wood-fuze shells recovered from civil war sites.
I think it's highly unlikely that a wood-fuzed shell would be re-worked to accept a Bormann fuze. A wood fuzehole would require a significant amount of skilled labor and tooling-work, to ream out the narrow woodfuze hole's walls into into precise-width levels, without "chipping" the brittle cast-iron, and then tap new threading. We know the Confederates were short of skilled ironwork-machinists. Rather than commit to such labor, I think both the US and CS Ordnance Dept. would be more likely to just go ahead and issue the old woodfuzed shell for use. (We know the yankees made that choice, firing dozens of woodfuzed shells during the battle of Shiloh, April 1862.)
Uprdwate:
I got a notification that another reply had been posted while I was typing mine. Emike's reply reminded me about the Mexican War era US Navy "Boarding Grenades" that were found among the artillery shells from the exploded ammo supply ship at City Point VA. Those grenades had a longitudinal moldseam.
By the way... please email me several close-up photos of the Bormann fuze in your Selma-found 6-pounder. I may me able to identify it as US or CS-made.
Regards,
Pete
