Go to LakeLinellc.com
He has a really nice set of steel fiber optic sights for the G2/G2C/G3 series of pistol. I have them on my G2 and really like them A LOT. It is a simple screw in replacement and you fit the fiber optic wires with a lighter or soldering iron. Excellent deal at $40. They really pop, even in lower light situations.
Additionally, if the gun will be shot a lot, go ahead and get the stainless recoil/guide rod assembly and the stainless steel striker sleeve. Easy to install and there are videos on how to do it. Lastly there is an aftermarket trigger that does away with the glock trigger gizmo. With the frame mounted safety it is redundant and can hinder an otherwise decent trigger. I have seen/shot several of these guns and two of them needed the trigger safety modified/replacement.
I did all of these mods as I don't like plastic parts in my guns when it comes to critical moving parts. Not needed for a lightly shot gun, but I'm around 2k round count now and have had ZERO feed/function problems except for one brand of ammo. Feel free to ask if you have any questions