great piece, and one I've not seen before. Looks like an early issue back with a typo or misprint - it might be along the lines of the 'Leichester' typo that has only recently been outed. The big question is what is under the sticker.....
the standard Slave 1 back is here - same text as the sticker
I always suspected that the three colour ESB back was an earlier issue than the all blue back below - the sticker would seem to prove that.
edit: or maybe not as the 1st issue ESB is also Y-Wing TM (as are the SW issues)
Am loving that blue background 8)
and for completeness - 1st issue ESB with no Slave 1, but still with the same Y-Wing TM text