VD 16, the bibliographic database of sixteenth-century German printing, is older and more complete than VD 17, the equivalent project for the seventeenth century. One thing I very much like about VD 17, however, is that Schlüsselseiten, or facsimiles of important pages, are available for the majority of editions. Sometimes an entire pamphlet is available. I love that.
In the late "Wilhelm Friess" editions, there is a defective passage. I've looked at several of the late editions, and they all have the same defect. For one edition, the passage is, frustratingly, just a few words past the end of the last of the Schlüsselseiten. I could order a facsimile to see the reset, but I'm not sure if it's necessary.
Microfilm is a much more limited medium than digital facsimiles, but microfilm or copies made from it are sometimes available without charge by interlibrary loan. Searching on WorldCat, it looks like a copy of the edition I'd like to see made it into a microfilm collection owned by a dozen American libraries. It can't hurt to ask, so I put in a request.
The copy came yesterday. It's not the same edition. Comparing the title page and other Schlüsselseiten from other editions, it's clearly an edition that isn't recorded in VD 17. It still has the defective passage, but at least I can add another item to my list of "Wilhelm Friess" editions, now up around fifty entries.
With WorldCat and other bibliographies, you often have little more evidence than extremely slight differences in title formulas to decide if two editions are the same or not. Sometimes they are, but sometimes they aren't. By the time an American bibliographer who may not know German has decided what to do with superscript vowels, early modern capitalization, and non-standard punctuation, all possibilities for distinguishing two editions may have been destroyed. This is one more reason that I remain at least somewhat skeptical until I see something with my own eyes, at least in facsimile.