Unlike the J416-J417/P488-P489 where some strikings may be original, this design is a restrike made in the early 1870s.
It uses a heavily polished reverse die such that features in the lettering have been worn away. Notice in the image below the broken letters such as the "S" in "States" and "Cents", the "D" in "United", the "F" in "of" and the "A" in "States" and the second "A" in "America".
Breen described this reverse as an 1868 die but I have not seen any 1868 shield nickels with the reverse in this die state. I date the striking to circa 1870 as the die in this overpolished state was used to strike regular 1870 proof nickels as can seen below. If the first "S" in "States" is any guide, more of it is missing on the 1865 striking thus it appears that the pattern was struck after the illustrated 1870 piece.
Shield nickel expert Howard Spindel notes an 1869 business strike die which has the broken "S" in "States" and broken "D" in "United". Perhaps this die was polished up and used to strike these as well as 1869 and 1870 die trials and some 1870 regular issue proofs as shown below.
It is also the same reverse die used on the off-metal die trials of 1869 J687-J689/P768-P770 and 1870 J805/P893.
Over a dozen are known as illustrated in nickel. The existence of an example in copper of J419/P491 has not been confirmed.
White metal reverse splashers JA1867-19/P3281 are also known.
Photo courtesy of Bowers and Merena. The photo of the 1870 proof is courtesy of Heritage.