I wonder about that video...the selective fire Glock is the model 18 not a 17.
The only one I've ever seen fired was during a Glock armorers school by an instructor from Quantico. He told the class that he had fired every fully automatic weapon ever made and that the m-18 Glock was the most controllable. He wrote his initials at 25 yards with a 30 round magazine. I'd like to see him use THAT magazine! Wow!