I got this a couple years ago and never really paid it much attention (nickels aren't really my thing). It's obvious that the obverse is a lamination error, but what about the reverse?
Actually.. It looks like it was struck on a Split Planchet. Not a Lamination. Struck on the Reverse Half of a Split Planchet. Can you give us the Weight? Or show the edge.
Would a pic of the edge, or a measurement of thickness help? (I'd have to dig it out to do either, but I would if it'd help)