I edited my response.
Yes, that is sort of what Lafontaine said, too. So, yeah, there does not seem to be an inherent contradiction between the two. Gallez's thesis is much more nuanced than I previously thought. Before, I used to reduce it to Nazarenes' writing the Quran, but this does not seem to be the case, nor is it an accurate representation of his actual thesis.
I'm not aware of a changing in Gallez thesis about "Judaeo Nazarenes" writing the Quranic rasm...