This does look like the 1956-D WRPM-018 and coppercoins 1956D-1MM-020
http://www.coppercoins.com/lincoln/...ie_state=ldsA side by side confirms it, While the coppercoins example has a hook to the west at the top, we have to consider the die state of their coin. It is a much later die example. Looks like a match to me.