I look forward to hearing more from Persian speakers on possibility of actual words or perhaps phrases in this acid etched motif. While as I have stated my sense is that this is a genuine tribal Khyber which has perhaps entered the Kalash (Kafir) realm, possibly a trophy.
Since like much of Afghanistan, Uzbekistan (Bukhara) Sind and Baluchistan, who all had profound Persian influences present....this was probably quite so in the Nuristan regions. However, it should be noted that the Kalash have tried to maintain their animist religious tradition and beliefs in autonomy in the areas of Chitral where they relocated after Rahman Khans incursion in 1890s.
It is curious to see such motif and affectation applied in what appears to be regarded as in Persian style but with Kalash images coupled with supposed Persian script and dating.
Could this be some sort of syncretic anomaly?
Here I would note that with decorative calligraphy, it has often been presumed that in many cases it is in effect 'jibberish' or simply approximated lettering to achieve a provocative result in imbuement of a blade.
This was the case with the heavy lettering used on Sudanese blades in the late 19th c. known as 'thuluth'. It has been discovered however, that much of this decorative calligraphy is typically in reality select phrases or wording from Koranic Surahs in numbers of examples. This however is used in repetition and sometimes with added contemporary invocations related to the Mahdi.
In the case of Persian decoration, the well known blades of the Persian trade blades of the early 19th c. (well described in Oliver Pinchot's " On the Persian Shamshir and the Signature of Assad Allah", Arms Collecting, Vol. 40, #1. Feb.2002) he details the fact that these blades were decorated with a cartouche holding the Persian lion image to represent the famed makers name. While with scripted cartouche as well, this pictogram served as recognition visually for less than literate clientele. These were the kinds of considerations often used in decoration of these blades in these times of far broader availability of weapons.
Perhaps this 'decoration' is also in such manner, and Ed's suggestion is of course well placed. Hopefully Ariels resources will find for or against the matter.