Both of these handwritten entries appear quite often in the earlier volumes in this or in similar form. They are usually located before the title page, sometimes on the inner side of a book’s cover.
In the case of stamps, those depicted below will most likely be the ones used. The stamped image is usually on the title page. A Leopoldina emblem and/or seal are often found glued on that page as well. The emblem can also be found embossed on the book cover. This, however, was not done on original covers.