As Mark stated the gaskets are correctly installed if on the sides only.
The biggest issue I've seen with the Harman's is setting the combustion fan cover plate properly. You will need a draft gauge and a little time to burn both at idle and high fire to make sure. If the cover plate is too far open the static pressure in the stove will be too high (should be a draft of .02 to ,04 inches of water negative pressure). There is a small allen plug in the front of the stove which gets removed to insert the draft gauge.
Even though you may have great draft in the chimney, improper stove draft can cause serious corrosion of the hopper and even worse, CO in the house.
Hope this helps.