Regarding the Küstrin bible and its alleged markings, I recently ran across the following: according to Krieger, said bible (picture!) was kept at Schloss Babelsberg at the beginning of the 20th century. No idea why or what happened to it, last mention I could find (also by Krieger) was a 1914 exhibition in Leipzig. Elsewhere he says there's no way to tell if the passages were indeed marked by Fritz or not, but if you want a list of them, here is a report from when the Historical Society of Potsdam got a look at the "relic" in 1863 (p. 27). Spoiler: the list doesn't include Pslam 73. :P I'm still skeptical.