Well aside from the movement being an old pocket movement and the cases on observation being pocket watches slipped into a bracket to hold them, or another watch case; it is pretty easy when the seller even tells you, "This originally pocket watch has been adapted to wristwatch." You must read the descriptions very carefully to see if you are being feed a lot of double talk. The more the seller writes, the more closely you need to read, he's covering himself. The two you posted are great examples and I would encourage you to go back and see how many things you can find that tell you they are pocket watches. Example: Why do you think the one watch has the sweep seconds dial on the left side?