Like many Glock owners I know, I had stopped at “Generation 3” of perfection. I had a Gen 4 Glock 17 for a short time. Had a few qualms with it, so I stuck with gen 3.
Until a couple of weeks ago, then I picked up a G19.5 MOS. Perfection sure has changed over the years.
The Gen 1 , 2, and some Gen 3 Glock pistols had a notch cut in the front bottom of the grip. This was to aid in pulling a magazine out of the pistol. The first Glock magazines were designed not to fall free from the gun. This notch is not very popular in the US. My self and others have gotten blisters on our pinky fingers from shooting a good bit of older Glocks with this notch. Much to many dismay, that notch came back in the Gen 5 pistol. At least for a while.
The MOS pistols, cut for optics, omitted this cut, and added front slide serrations.
Glock announced on Instagram that they are removing this notch and adding front slide serrations to model G17, G19, and G26.
I imagine these earlier Gen 5 pistols with the mag notch and with out the front serrations will be considered a little less desirable than the newer ones. Maybe they will show up on the used market at a discount as people upgrade.