Hmmmm I don’t think so.That is to change the backstrap. here is the manual, scroll down to see it. Page 24
That hole does have a perfectly legitimate function, It's a dust, dirt and grime collector for the backstrap, heaven forbid that gunk ends up on the palm of your hand.Hmmmm I don’t think so.
Although the small round holes are there to remove the roll pin the small square hole on the very back of the backstrap does nothing to facilitate the backstrap change.