These ksav Ari tefillin parshios were identified by my battim macher, (battim repair expert) Reb Yaakov Yosef Schwartz as having been written by the famous Reb Nachman Sofer. This sofer wrote tefillin for many well known Chasidic Rebbes. He was alive until around the 1980s. I have not been able to find information on him so if you know anything about him please contact me and I will update this post. One thing is certain: These parshios are very nice. The ksv is thick which is most apparent in the thin lines. Each letter has thick lines and thin lines. In his writing the thin lines are thick enough that there is less likelihood of cracked letters when they get old. Another interesting feature of his writing is that he has the extra taggim (crowns on the letters) of the Shimusha Raba (one of the geonim) on many of the letters. Look at the top line, third word in from the right, the word יבאך. In this word you can see taggim on the bais, alef, and kaf sofit. Normally, there are no taggim on an alef and on a kaf sofit, and only one tag on a bais. On the other places where there is a bais, he has no taggim other than a small tag at the beginning of the letter. Most other soferim make a full tag on the letters bais, dalet, and kuf. The Mishna Berura calls the taggim swords, which are used to fight against the yetzer hora.