Is this normal for the motor to seal the hatch lid with a gap?

 

Normal? Yes. Correct? No.

There are 3 ways this seems to happen.
First, the hinges on the body side of the car have a slight bit of fine tuning/adjustment. My 89 needed about 1/8" of an inch, and some adjustment here worked for me. Yours looks like a lot more than 1/8", so I doubt this will work for you.
Second, the rear decklid/spoiler section is attached with some sort of adhesive, and can actually slide back on the glass over years of being under pressure from the struts. This is fairly common. The glass stays put, and the decklid...slowly...slides...back. You basically have to take it apart, clean it, and reattach with new adhesive. Sounds scary, but I've heard it's actually not too hard. I'm fairly sure this will be needed on my 88. Will probably tackle it in the next few months.
Last is the actual metal hinges bend a little, and honestly it almost looks like this is what's happening. The whole hatch glass and decklid seem to sit ever so slightly lower, and farther back than intended. I don't have any experience with this, but I've recently discovered people discussing this, and how new hinges fixed it. Hawk's Motorsports makes some really nice billet hinges, but they're expensive. I've heard several positive reviews, though one guy recently posted about some glass breaking issues and isn't sure if it's the new hinges or not.

I might take a good look and really see if you think you can determine what's causing it. Also curious to see what other members think. I'm no expert, though I may be after repairing my 88!

 

Much appreciated for the info! There is a pretty decent gap at the top of the glass hatch to the body.

 

If ya look at the upper corner of the glass, compared to where it's supposed to fit the contour of the body, it almost looks low and back. Which would of course be why your decklid sits back too far. Seems to me if the hinges were bent, this might be how it would sit. Like I mentioned earlier, there's just not much adjustment on the body side of the hinge, and if it was the decklid that was pushed back off the glass, then the glass itself should still be in the right place. ...but again, I haven't actually been through the hinge issue so I'm not 100% sure exactly HOW it affects the hatch alignment.

 

Is the metal trim connected tight to the glass at the top of the hatch glass where the metal trim comes together? Mine was separating up there and needed to be resealed.

I went through this recently on my GTA, yours is not too far off and as mentioned new hinges might do the trick. Mine was further off than that and I removed the deck lid, repositioned and re-sealed it. I also tried the Hawks hinges first but didn’t help mine enough. If you do remove the deck lid to reseal push the deck a bit more in than perfectly flush, once everything dries and seals and the hatch struts are reconnected that will push the lid out just a bit. I saw that in the factory service manual.

 

Hinges don't look in bad condition