Hello I am not sure i am posting this in the right location and i hope someone will help me out. I have never owned a pellet insert before and i am looking to start used as the cost of new is so high. I have found a used Whitfield which i believe is an advantage model. The owner is asking $600 for it and it does look very nice in the pictures. I am thinking the unit is from the early 1990's but not positive. Can anyone give any insight on this please. I am supposed to go look at the unit tomorrow. Thanks in advance. The picture is of the information on the back of the unit.