It's what those last two guys said. I thought a scan would help you see the distinctions. As for the fronts, they look about the same. The -2's have blue ink captions and are easily distinguished.
I think you can find 11 Cubs among the E90-3's...
Archer
Brown
Chance
Cole
Evers
Hofman
Overall
Schulte
Sheckard
Steinfeldt
Tinker