I think that is not possible. But I am not an expect at Glock series.
I am a lefty too. I own a TM hi-capa 5.1 and I looked into changing that. As for my case it is not really possible. Most major parts of the gun need to be mirrored for this to be possible.
Plus I used my pistol as secondary. As a result I practice my pistol with right hand and primary with left hand. It allow for better response during CQB games.
p.s. If it is your first gun, I suggest that you get a primary rifle first and leave the pistol for a later purchase.