I have extracted this from the Bustamante Peruvian Stamp Catalogue:
"Of this third issue, several reprints were made that motivate interesting varieties.
Of the blue money, up to 5 have been correctly studied, having made 3 of them with the original plate and the following ones retouching it.
In the first impressions, the margins between stamp and stamp are very narrow, barely 1/2 to 1/ 1/2 mm. In the retouched reprints the stamps are separated from each other by a margin of 2 to 2 2 1/2 mm. In very rare occasions these margins are larger.
In the first impressions, the letters PORTE FRANCO are all the same size and the quarter of the shield that contains the horn of plenty has 36 lines and the zigzag is not interrupted at the angles. The third reprint, maintaining the same characteristics of the two previous ones, also presents the background of the horn of plenty or the words of the frame, totally or partially on a plain white background; in this third impression the zigzag lines appear interrupted at the corners. All these varieties can be found combined, and they are the result of the wear of the plate.
The main characteristic of the fourth retouch is that the fourth line that passed through EOS of the word CORREOS on the right has been erased (n6k) and gives the impression that a white stripe passed behind the letters. The words PORTE FRANCO are all at the same height and this detail differentiates it from the fifth retouch in which the letter O of PORTE and CO of FRANCO vary in size and are larger than the other letters.
In these 2 retouches, the background of the field of the cornucopia has been re-engraved and represents 33 vertical lines instead of the 36 that the original stone has. The last touch is the most abundant of all the "little coins" of this issue."
In addition, the only three truly fake copies that I have been able to see are here
http://www.peru-philatelic-study-ci...015-7-18.pdf and none of them match my copy because the shape of their shields is very rough in my opinion.