Kind of a side discussion I suppose...
The holding power of cut nails lies a bit with their being flat or squarish. First generation "French nails" about the turn of the 19th century typically did not have heads, or the heads were bent over "L" shaped. Heads often being squarish or pyramid shaped.
IIRC, wire nails are more a product of the post CW "Bessemer" age of the 1870's/1880's such Bethlehem Steel's Gautier wire mill in Johnstown PA where my great-grandfather worked mailing steel "wire" for barbed wire fencing and nails. Wire nails being round shafted lose some of the gripping power over time as the wood fibers move.
IMHO, if historically duplicating a period packing box, one should duplicate or attempt to replicate what was used in its construction based on the box one is looking at.
I would be surprised to find wire nails in CW boxes as largely too late, and hand-forged wrought nails as largely too early and relics of a 1800ish pre nail machine world. But, if a documented CW period box had either, then they should be used in the historical reproduction if "authenticity" is involved or matters.
Others' mileage will vary....
Who's wife's grandparents' 1880ish farmhouse burned to the ground last week, leaving a foundation, ashes, and many cut nails. Although I have a wrought nails from their spring and smoke house built in 1832.
In gleichem Schritt und Tritt, Curt Schmidt
Not a real Civil War reenactor, I only portray one on boards and fora.
I do not portray a Civil War soldier, I merely interpret one.