Tim,
I have never seen a wootz blade on a piha. Most look to be laminated and possibly some were differentially hardened similar to a Japanese sword. Many of mine have striations in steel very much like the older kukris I have.
I have one piha with very distinct streaks of nickel in the blade.
There is a reference to the fine quality ore found in Ceylon in at least one of my articles. I'll see if I can find it. Most people don't think that quality was reflected in the blades produced there.
From what I've read, the more ornate metalwork on the scarbbards (like yours) came later. That and the elaborate work on the knife itself would be indicative of a gift to honour a person of rank, possibly worn by a chief. I doubt it would have been a useful fighting knife! The phrase "just sit there and look pretty" comes to mind.
I don't know for certain what a fighting piha would be, but maybe it was a plainer version like this:
