Well, I've never been one to be so picky about the actual name of this part - but if your are going to pick nits - at least be correct.
It is not listed as a "slide lock" or a "slide release" - it is a "slide stop" on the parts list.
You're right. I made the same mistake that earlier poster did when I looked at the parts list -- picked the wrong part.
But, if you're going to nit pick, do it right: it's actually called a SLIDE STOP LEVER
The unaddressed point remains: if that lever didn't have dual functions -- both holding the slide open and ALSO releasing the slide, there would be little reason for Glock to offer an extended version -- as the extended version doesn't stop the slide a bit more effectively than the standard version... It does make the process of returning the open slide to the closed (in battery) position somewhat easier -- which is arguably why some folks make the mistake of calling that little pressable platform on the lever a RELEASE!!