I got mine replaced at Speedy Autoglass back in 2017 if I remember correctly, not at a dealer. Not sure what you mean by 1/2" gap at bottom. If you can provide more details I may go and have a look. But then again, mine is not the original even though OEM windshield was used.
Just looked, and there is practically no gap at all. The windshield sits right on top of the trim, or should I say the plastic trim touches the bottom of the windshield, pretty much across the whole bottom egde.
In your case, it maybe that the trim piece was loosely atached, and may just need to push it up a bit. Cosmetics only I hope, you will be fine as long as no leak. No harm to check with your installer if convenient.
I had my windshield replaced by Safelite and I chose Honda OEM glass. Everything looks fine but I notice the rear view mirrors seems to vibrate a little more meaning when you look at it when driving, you can see the cars behind a little shaky. If I reach out and grab it then the image become more stable. Not sure what's going on.