This is considered to be the regular dies trial piece in copper of the 1867 without rays design. These were normally sold to collectors as part of complete copper sets, but this particular die trial does not appear in the known sets, Garrett's and the virtually complete double set which was apparently stolen from the Iowa State Historical Museum. Those only had the with rays nickel J572/P648.
It was struck from two reverse dies illustrated below courtesy of Stacks.
Reverse of 1866 J573/P649 with the stars above the word "Cents" pointing between the "E" and "N" and between the "T" and "S". This reverse was used on many 1866 nickel patterns including J507-J509/P591-P592.
Note: Regular 1867 proof nickel examples, from this reverse die are also known and are extremely rare with only about 2 dozen believed to exist. Examples include the Morgan-ANS set, the Stacks 10/2003 Rothchild sale which was part of the Garrett 1867 proof set and 2 others that were in Heritage 11/03 sale.
Reverse of 1867 J573/P650 with the stars above the word "Cents" pointing to the "E" and "T". This is the more common of the two and is known to exist in both proof and business strike format.
About a dozen combined are known.
At least 1 example in copper is a mint error struck on a cent planchet and should not be confused with the copper die trials. For additional information about this, click here.
White metal splashers of the second reverse JA1867-19/P3281 are also known.
Photo courtesy of Stacks.