Thanks orstampman.
I saw this stamp sell today on
ebay (item
318665748208), a "coil" of the $1 from the same series. The stamp is obviously not trying to deceive anybody, it was probably just carelessly trimmed off the envelope or package. The point being, the left side is a natural straight edge, showing the guideline at the edge of the pane. Notice how jagged that cut is, compared to the scissors cut on the right. The little dimples are not a sign of perfs being cut off, that's just how the paper was cut back in 1903.

