Great find! Thanks for sharing!
I think that #3 on the right upper ear platform is the number for the metal ear parts. It is possible that #1 is the left ear, #2 is the right lower ear and #3 is the 2 part upper right ear. There's only one way to verify this, and this involves the removal of the ears from the helmet (I assume that these are screwed to the ear platforms). The physical gauges all over the helmet shows an ESB-like paint pattern and not the Pre-Pro #2 paint pattern.
As BGHunter said that 2012 was the year of the Pre-Pro #2, the summer of 2013 belongs to the Boba Fett helmet and its re-discoveries and new acquisitions.