Yep, Machine screw threads. Maybe 10-24 size, but take one to the hardware store and check with their screw gauge. A Helicoil kit will fix up any that are stripped out. But if the screws thread in and hold reasonably well, they're probably fine. It doesn't take much torque on the screws to hold a panel on.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.