Hello Italia899 I cant tell from the photo but is there a vent on the top stove plate under the lip and did you try to contact harman they could tell you what year it was made. http://www.harmanstoves.com
I know the sf 250 has a second dairy smoke chamber where the fan pulls air in around it to make it burn more clean before it exit out the pipe other then that i do not know what it would before. inless someone tried to put one in themselves. I would try Harman and see what they say.