Those are a little trickier by themselves, on a packer you have the very fatty point in place to help protect the flat along with the fat cap. Does the heat come from underneath on your smoker grill? If so, then you’ll want the fat cap DOWN, this will help protect the very lean flat. If you have some form of reverse flow, with a baffle to direct the heat up above, then the fat cap will go up. My smoker, heat comes
From the bottom, so fat cap down