The great thing about Glock pistols is how modular they are. Assuming for an instant that all of these pistols are chambered in the same caliber, then the parts are interchangeable. Of course, you can't fit a long slide on a small frame, but you can swap out all the standard size parts. And all of the larger magazines fit in the smaller frame guns.
And all the working parts are located in the same places.
This is a great collection of Glocks. This guy is ready to rock and roll.