Belay that order!
Turns out that those aren't the correct screws after all. The guys on the Pontiac website provided me with photos of what the original screws are...and they coincidentally look just like the regular, round indented, philips head wheelwell trim screws I randomly grabbed out of my toolbox and used on the car in place of what I thought were the right screws.
You gotta love when the haunted tool box knows more than you about what the right fastener is, for the job at hand.
