Grill is fake and on the wrong design. Note the secret mark at upper right, that says it is a Continental or later printing. The grilled issues were printed by the National Bank Note Co. Most likely a Scott number 161 or possibly a Scott 188. Corner margin singles with very large margins are often trimmed to appear imperforate. Typically the left or right vertical sides have a natural straight edge and the balance of the sides have their perforations trimmed away. The fact that it was cut close at the bottom says take a closer look. You may even be able to find tiny nicks on the edge which are the bottom of the original perforation holes. Your 1 cent stamp had several tiny indentations that could be the remnant of the original perforation holes.
Micarelli has a footnote for Scott 161 that indicates a few were produced with an experimental J (7x9.5 mm) grill. He also notes that these were considered essays. But in their essay section, Scott makes no mention of imperforates for 161-E1. Don't know if this helps but thought it worth mentioning. Added: Have to agree with the others ... trimmed.
The only Continental grill essays Scott lists in the essay section are grill samples without a printed design. They are given the Scott number 79-E16 and placed back with all the other grill essays which preceded them in 1867. Those which were printed with designs are listed as sub-varieties of the issued stamps from the Continental Bank Note Company 156-166 and 178-179.