umm.. I think it was in 1989 when they STOPPED manually punching the MintMark. Thus you don't have RPMs after that. Since you ALSO have a ZINCOLN .. I can pretty much guess without looking closely why you think it looks like an RPM ...
No Looks like a worn die strike. You have DDD - Die Deterioration Doubling. Worthless doubling. By the way.. The correct numismatic terminology is Doubled Die and they fall into the Variety Category.
Here is the explanation - http://www.error-ref.com/die-deterioration-doubling-incuse/ Suggestion - please create your threads over at the Error Coins forum.. Not the What's it worth forum. Many minor issues have very little or no premium at all. Worry about value last.