The notch isn't as significant as the extra thickness of that leg of the R, it's just the only noticeable separation if this is a DDO (which I'm pretty confident it is).
This one has identical doubling and mintmark placement, but my coin doesn't have the markers: http://coppercoins.com/Lincoln/dies...ie_state=mds
This one has identical doubling and mintmark placement, but my coin doesn't have the markers: http://coppercoins.com/Lincoln/dies...ie_state=mds






























