My sample size of 2 frames leads me to believe that the frames come straight off the line and into a shipping box. Minimal checks and adjustments, if any. If assembled into a firearm, they get checked and adjusted.
Congratulations, you get to do all the final assembly to put it in working condition. I do wish they would get rid of the roll pin nonsense. I may buy some drill rod or something of the correct size to make solid pins but in no hurry.
The slides have been pretty good out of the box. I did have one that was warped but they replaced it. All the others have been pretty accurate in that they swap around to my various frames and fit the same. Dagger slides are the only aftermarket slide that I correctly get the firing pin rattle safety check. I've had to replace the striker spring with an OEM to get the other 3 brands I have to rattle correctly. The updated striker is supposed to be fully compatible with Glock gen 3 now. They changed the tip design.