The locations of the two listed mint marks from coppercoins 008 and 022 are not in the same locations as the OPs coin. But I agree it is a RPM.
Side point: There was an issue with a damaged mint mark punch in the late 80's cents. It left the mint mark looking like this:

Note why I determined it was a damaged mint mark punch issue. The damage was all on the left side of the upright of the mint mark.

Other examples I found.
Edited by coop
11/20/2017 8:57 pm