Originally Posted by GZA
Yes. The springer models an older version of the Glock 17 (Version One, I believe? Someone can correct me if I'm wrong), where the GBB models the most recent version of the Glock 17 (Version Three) - these versions differ by these slight cosmetic differences (and other differences)
To correct a little, the springer is modeled after a Gen two Glock, whereas the GBB is indeed a Gen three.
Huh, this is... quite an old thread...