Indeed it is both, much as many if not most edged weapons in SE Asia as well. Most of the dha's and various forms are used by tribes interchangeably as both tools and weapons as I have understood. I am sure those well versed on the weapons of these areas may better elaborate, but in old National Geographic magazines there are often wonderful photos of tribal figures in these regions chopping wood etc with various weapons.
There are of course many examples and anecdotes regarding this, far too many to deviate from our focus on the piha kaetta.

Now to focus in on the Piha Keatta namely in the bird head use on the original style hilt and on the peculiar parrots head at the end of the scabbard. Birdshead decorated hilts seem to have fluttered in from South India and also have graced many fine daggers in Mughal times. In fact, the reality is that over many centuries Indian craftsmen have been openly invited to the Sri Lankan Royal Workshops. It is hardly surprising that inter related designs have permeated Sri Lankan form... naturally and in ways linked to Buddhist and Hindu styles...as well as the obvious regional influences.

Below are a few examples of Indian Bird hilts and the effect onto Sri Lankan weapons...in this case I focus on the Parrot-like Piha Kaetta scabbard tips.~

It is said that the name of the stylus is
'ULKATUVA' used to train a student to write on a palm leaf. Once he is trained he is permitted to use a different type of stylus the 'PANHINDA'
I had previously placed the stylus name as Keynithuth but will recheck that source...

The materials decide what the name of the style of dagger is called ...In the case of Crystal; Gal Mita Pihiya and below a Met museum example..

What seems to be the original form hilt appears at

http://www.vikingsword.com/ubb/Forum1/HTML/001998.html and above in my previous notes..Here is the bird hilt again ~

I am somewhat inspired to create a likeness post comparing the scabbard of the Kastane with that of the Piha Kaetta in the formation of the birds head parrot design at the tip.
see http://www.vikingsword.com/vb/newrep...ote=1&p=224117


This would also point to the same workshop which we know is true ...Kandyan Royal Workshops ... with the added assumption of the same timescale ...Thus the two weapons being made in tandem in this environment...

Same workshops, same time, same design.

To remind readers ~ Piha-Kaetta

A Ceylonese knife. Usually a broad single-edged steel blade with double fullers along the back edge to the forte, partly covered on each side with partly pierced silver-inlaid brass panels. The blade is often cast and chased with dense foliate motifs. The grip is usually carved ivory or wood mounted in silver and has a silver pommel-cap, with scrolling foliage worked into the cap.
These elaborately decorated knives were usually the product of the "Pattal-hatara" or "four workshops" with the blades being supplied by the local smiths. This was a mainly hereditary corporation of the best craftsman who worked exclusively for the King of Kandy. Originally there was only one "pattala", but this was subsequently divided into sections, which included a "Rankadu pattala" or "golden sword workshop". As well as being worn by courtiers, these knives were given by the king to nobles and high-ranking officials.