A shame that other than being briefly published, that this sword and swords of the type did not develop further in discussion.
The subject of the "Story Dah", as far as I am aware, has not been ventured in to in detail. I note Mark had added a little more insight and detailed images here;
It is my hope that Mark might chime in and offer some further first hand insight to this sword.
Personally, I think this sword dates post 1858, supported by the many and various Burmese silver collections held in Museums around the world.
It was the British Raj period that bolstered this fine age old craft, the period being 1875-1945, although, I understand that the 1860's saw the initial rise in export silver.
A point that I do not think Mark photographed, is what I think is a face from which the upper suspension loop protrudes from the mouth of.
If I am correct in my suspicions, based on others of the type known to me, this is the same face seen on the pommel, a face that I suspect is Hanuman... even the goodies had teeth and tusks...
I do not mean to be disparaging in my visual assessment of this sword, and for learning and discussion purposes, and that it is only my personal belief based on the examples I know, that the hilt on the example pictured is a later replacement... exactly how later I do not know, but I suspect post WWII. The level of carving is in my honest opinion, not consistent with known ivory carving found on these sword types or comparable carved ivories from Burma during this period. the method and quality of the craft which binds the antler is also questionable, I get an almost Laos or Thai flavour from it.
In the description Mark provided in his further research of the sword, he notes the panel on which 1798 is found on an added panel whilst the blade dates to 1919, a quandary indeed. On one example known to me, it has the English Royal coat of arms in repousse for this panel. Possibly this sword had it too, removed to fit this addition?
Of the blade type, it is a quality blade and considered by myself and others as a mid 19th century type through to the 1920/30's. I find from this point on wards that the blades decrease in size and quality as does the dress, finally to a point from the 1950's on wards where these swords became just a shadow of their predecessors with poor quality blades of roughly the same form and very lazy and poor quality repousse in pot metal. One such 1950's pair of swords known to me were purchased during an officers stay in the Kachin regions of Burma...whether this became a point of sale area or a manufacture area of the later types, I am unsure.
There are many online reference points for old Burmese silver, various combinations of word searches will present a wealth of information.
All for now.