upper intake manifold

I have a 3800 Gen 1 with an aluminum upper intake. I cannot find a gasket anywhere online. The rubber one they send doesn’t have anywhere to seat into lower intake. Here are the pictures. Any help would be great appreciated. Do I need to just use RTV gasket maker and go from there?

I had a decent coolant leak, and the mechanic said the plastic elbows were urgent, but the upper intake manifold gasket and valve cover gaskets also had leaks. I can't remember if he mentioned about the lower intake manifold gasket or not. I had him do the aluminum elbows and I wanted to do some...