Actually Rick using small nails for attaching silver plates were in use for a couple of centuries. Repoussed silver plates are also old. And based on the okir, I believe this to be Maguindanao also.
Here is my silver covered kampilan where all of the silver and silver alloy repoussed plates are attached by small nails:
http://www.vikingsword.com/vb/showth...ilver+kampilan