Very interesting question!
I'm sure you have 0.5 mg
alprazolam. But I don't know whether it's an old or new imprint.
I found pictures of both styles - 257 below GG and 257 on the side after GG.
Check out this website:
drugdigest.org - GG over 257
I also found a dated photo - 2002 - with GG over 257 at eckerd.com
A little history is warranted here. About a year ago Geneva (GG imprints) became Sandoz. So it's possible the imprint styles changed along with the name change. But I think that your pill is the current imprint and that it hasn't changed since 2002.