I think I have already been there. Back in the late 70s and early 80s I trumped over much of that battlefield. It is hard to even find somewhere to hunt there now besides most of the relics being gone.

To answer your question it seems like I have read that NC troops did use some of the rubber buttons and I have seen a kepi with a rubber button for the chin strap but it was not a military button. but I can't remember where. However, eyeballing the ground in Portsmouth Va. around the previous Gosport SY area, there are many very early rubber buttons with Goodyear B/Ms found. That area was camps from both sides at different periods of the war. However, rubber buttons were not being manufactured by the Confederacy and when the pre-war supply was used up, something else was used.