None of the plates i have found have holes.
The big piece has holes, but not the small ones.
cedar bark was woven over the big one and now i think the small ones where lashed in, think about it, its like pockets,you slide them in, if you are going in battle. , it would make it easy to repair and light when you run far away.

after thinkin bout it, we got 3 where we found the big piece.
as pointed out , the piece has 2 chop marks in it, which would explain why it is laying on the ground.
you can see what my diggin tool did to the copper, think what a sward or knife would do.

the guy makes it, the guy goes and fixes it and is ready for battle.
on this page you can see some cedar cloths, think cedar armor.

its a real cool read.
http://www.milkywayjewels.com/nwi_jewels.html