Can I burn wood in this fireplace?
The firebox may be rated for solid fuel, but is the chimney constructed to handle the extra heat and the possibility of having a flue fire from soot and creosote deposits?

A natural gas flue is not a solid fuel flue. If the chimney construction was skimped on to save money, then no.

If your HVAC tech has inspected the chimney and found it up to proper standards, then maybe.