DOM, the cartouches are not in Arabic but the date is written in Arabic, which is why I said it is peculiar. Also if we go the Lunar way and put the age at 1880 something (don't remember what year you wrote) then it makes the sword more suspect. Because the seal we have on the sword and this style of swords are after the 3rd Anglo-Afghan wars, which puts us at around 1919 or newer.
That seal was first used by King Amanullah who became king in 1919 and subsequently started the modernization and standardization of the country and army, plus getting closer to the Ruskies, unfortunately that was his downfall since it pissed off the Brits and they used the mullahs to bring him down.