I do agree that on close inspection the parallel marks seem to be made with a single punch, which makes it difficult to imagine that they are an unintended by-product of the manufacturing process (like the grind marks). Asuming the punch marks were not made by a modern vise, clamps, or whatever, why would they have been made originally? They appear too random and inconspicuous to be decoration. Yet, it would have taken a great deal of attention and precision to punch in the marks in such a regular pattern. Some sort of tally, maybe? I just can't think of why they would have been put there.
