Very interesting John. Either Tom or George here or elsewhere pointed out a similar oddity on two 1960 backs. Conley ( 293) and Chiti (339) can be found with an errant "Batting Record" box ( Chiti at top back, Conley lower back) The box seems to appear on both cards no matter how cut. Just seems to be an out of place box on the sheet/. But yours appears much scarcer as the Chiti and Conley both have the box but in different degrees.
The Conley has front differences as well on the insert
