New analysis of f116v, Central Bavarian dialect

[Koen G]

To me, this indicates that the marginalia was added probably after 1500. Is there any reason to think otherwise?

Based on the handwriting, we are almost certain that the marginalia were written in the early 15th century.

The big problem is the "x" in "pox". German writers weren't too keen on the letter x, generally. You most often see it in Roman numerals, Latin loan words and a small set of other words. Replacing "cks" with "x" is very rare. Hence, the spelling of "pocks" as "pox" is also very rare. It's not impossible, but we're just unlikely to find any attestations.

What Hans Sachs writes in his vulgar dialogues ca. 1550 is as relevant to the VM as the swallowtail merlons of the Kremlin walls, which is to say, not relevant at all.

As for the goat liver in the Kitzbuhel law, this is only one attestation, which does not allow us to draw any conclusions about time and place. It's not because one scribe wrote poxleber once in one book, that only that scribe was able to write this word. 

Aga: I'm not sure if I'm following. The final letters in the VM are "x", those in the fragment you show are short-s. They are a different kind of charm words. Short words ending in x (rex pax nax type) vs words with Latin endings like -us.