Hello Kubur,
It might have been the case the blade was badly rusted and the original koftgari was damaged/removed during the cleaning process, then the old cartouche was repaired, or alternately, a new cartouche was added.
Anyhow, this type of cartouche is not very common on Persian blades but on Turkish blades (Persian blades commonly had different type of decoration- see photos)
The blade can be also Turkish or North Indian. Unless we see more of the type of wootz, it would be hard to tell the difference.
PS: Ariel, I believe there can be discerned at least two sets of criss-cross hatchings that would point towards a secondary repaired/replaced cartouche.