A couple of additional interesting observations : The 1967 "only" MPC, shows the License Plate rubber Shield, but no fasteners are listed. And secondly, the 1960-68 MPC shows the shield with 3, 352361-S100 fasteners required, and notes them as "No. 8-18 x 1/2", washer head, self-tapping screws", with no reference as to head detail (hex, round, pan, phillips, etc.). In addition, there is a footnote that this part is not supplied as a Service Part (ie, Factory only).
Bob