The sliding bar type I had years back was a safety catch behind a claw type hitch jaw. The pin rests against the half round claw....the sliding bar slide behind the claw keeping the claw closed around the pin. In 8 years no noise.
jaw type
I'm not familiar with Curts E16 jaw type.
OP...I would suggest dropping by the selling dealer shop and let them show/explain the proper procedures for this particular hitch. 5th wheel hitches use several different jaw type systems even in the same brands.
I'm wondering if the OP is referring to Curts E16 sliding rail hitch for short bed trucks.