To me it seems pretty obvious that this is an E93 due to cropping. Cropping is identical with the orange E93 below. It obviously differs from the purple E94 that crops at the bottom of the shirt, and also differs from the red E98 that crops between where the E93 and E94 do.
Yes, it is possible that this is from a yet-unknown E set, thus justifying and E-unc description, but if one is looking for distribution evidence and one is not convinced that it is an E93 because of the blank back, then there is certainly no reason to give it an "E" designation for "early candy", including "E-Unc". The only reason one would be led to the conclusion of it being an E card would be the remarkable resemblance to E93s, so the argument would become circular. If it deserves E-Unc, it deserves E93.
In the absence of evidence to the contrary, I think SGC made the right call in labeling it an E93. If it shows no evidence of trimming or other tampering, they probably should have given it a numerical grade.
JimB
