I recently moved into a 40 year old house which has a prefab metal zero clearance wood burning fireplace. It appears to be structurally sound but looks awful and provides very little heat. I would like to install a gas fired insert with a blower that would provide warmth as well as ambiance. My contractor tells me that most fireplaces have a knock out through which one can install the gas line for the insert. Mine does not. A label inside the firebox says it is made by Metalstamp Inc. in Savannah Georgia and is model Savannah 4228. I tried to find the company but it appears no longer to be in business. Is anybody familiar with their line or can you tell me if it is possible to introduce a gas line somehow? My only alternative is to replace the entire unit which I would like to avoid. Thanks.