@Abramthegreat . Can we see the whole coin both sides? The quality of the coin matters as to the value not just the fact that it may be a D/D in my opinion. Have you ID'd the correct Variety?
Its value is dependent on who you ask. As the RPM-001 it should be the the most sought after one for those than collect this type of error. http://www.varietyvista.com/02a LC RPMs Vol 1/1956DRPM001.htm
FYI.. It's a RPM which stands for Repunched Mint Mark. It falls under the Variety category. Variety A variety is a coin that differs from its basic design type in some distinctive way and is thus differentiated by collectors. Mint Error Coins with major mint errors as a result of human or mechanical error during manufacturing. For the most part, mint error coins fall under one of three headings: Planchet, Die or Strike. Nice find.
Nice early die stage FS-501 Die stage A with a bit of circulation. https://coppercoins.com/diesearch.php?date=1956&date1=1956&thismint=d&thistype=mmom&page=0 As @SensibleSal66 said photos of the whole coin will help as to a value. https://coppercoins.com/lincoln/diestate.php?date=1956&die_id=1956d1mm001&die_state=eds
