I posted the answer from the Heat-N-Glo website...

Can I remove the glass panel on my gas fireplace?
Not if your fireplace was shipped with a glass panel on the front. Direct vent fireplaces are sealed combustion systems and need the glass on to function properly. We sell optional screen mesh panels that go on the front of the glass that takes away any reflection, and adds an additional safety barrier against accidental contact with the hot glass panel. The other type of gas fireplaces we sell, called B-vent fireplaces, come with fixed, not sealed, glass fronts. You would need to check with your local dealer in the area to determine if the glass panel can be removed from this type of unit. Because removal of the glass is totally dependent on the specific unit installed, we cannot recommend that the glass be removed unless the specific model of unit denotes that it can be removed and the fireplace will still operate safely.

Here is a link that might be useful: Heat-N-Glo