Slowly external safeties are reapparing on other makers' striker pistols. But in the meantime even holster makers failed to see that a covered guard on a Glock does nothing to protect the user except keep a stranger from pulling the trigger (in the old Ranger's day, even trying was asking to be shot dead); while ADDING the danger of the covered guard catching the trigger finger of the unwary and actually firing the pistol.
For that reason I don't make gunleather for Glocks -- holsters lull consumers into thinking they have made their Glocks safe as they would've on their 1911. But in fact that is impossible; the pistol can still be fired in the holster and many, many, many have been fired in Safarilands. I've quite a long list of their shootings.