HI Mark,
As it happens, I discussed this inscription briefly on the first page of an article ("Kharoṣṭhī and Brāhmī Inscriptions from Ladakh") which is about to be published in Bulletin of the Asia Institute 30, pp. 93-111.
But I was not aware of the image of the inscription published in Neve's book, and had worked only from Francke's eye copy and J-Ph. Vogel's discussion.
Seeing now the original in the photograph in Neve, the eye copy looks to me to be pretty accurate. I agree with your colleague that the third and last character are very uncertain, as is the early dating. .
Concerning that, in the new article I say "Such an early inscription in Ladakh would be unexpected, but not impossible."
Regarding the marks above the inscription, it is pretty clear that they are not related to it and have no orthographic significance. For further comments on them, I would refer you to my co-author,
Quentin Devers, whom I have copied on this message.
Rich