Shelby sketch/assembly book calls out 55962-S9, an oval head screw to attach fiberglass panel to the body. (#8-18, 5/16" OD, 3/4"L). AMK provides a drill tip truss head (similar to the carpet screws, but a slightly flatter head, but not fully flat), I think it is 380660, #8-18, 1/2"OD, 1/2"L. S2 finish.
My Cal Special uses a different one (which would not be surprising at they were done by Ford not Shelby).
What is correct for attaching the fiberglass panel to the body for a '68 Shelby?
Part 2, I think a 52608-S40 is correct to attach the taillight buckets to the fiberglass panel. Filister head, AB (finer thread), #12-14, 11/32" OD, 1/2"L. Correct?