Now that you have the distributor out of the engine and in your hands, I would put it back together and just spin it by hand. This test alone will determine if indeed the noise is coming from the assembly.
You may also have a mismatched parts from different manufactures’, such as a rotor that that may have came from O Reilly’s and a cap from Wal-Mart, they may be correct for the application but the manufactures tolerances may play a part here.
From all the pictures I have seen nothing that really points out a problem area, but I have not seen a picture of the distributor gear and its end play gap.
