[A. G. Maisey]

In Central Jawa during the 1970's to 2010's most keris literate people whom I know & knew attributed this style of pendok to Banyumas.

As Jean has pointed out, it does have some indicators that could perhaps place it elsewhere, however, although North Coast blades are sometimes longer than than Central Javanese blades, these larger North Coast blades can be found in dress other than North Coast.

Similarly, a central panel of ornamentation is not unique to North Coast pendoks, it can occur in East Jawa, Ngayogyakarta & Solo pendoks too; it is much less common in Solo pendoks.

The type of central panel ornamentation that is common in North Coast pendoks, and that I have only seen in North Coast pendoks, is where the pendok has a very short central panel only a few inches long.

This pendok has a lis, the soldered or rolled collar at its mouth. This could weight origin towards the East of the North Coast, but it can also occur in a Banyumas pendok.

EDIT

One other possibility:- Palembang pendoks can have a pendok like this too.