what hardware for grab handles?

I'm looking at adding handles to the stock location on my '91. There are holes in a backing plate on the outside beam above every seat but the driver, but I can't tell if they are threaded for a specific bolt. 6mm bolts are too big, and 5mm doesn't seem to do anything, so I'm wondering if they are meant to be used with self-tappers or what.

Thanks

they are not self tappers, but I'm not sure what size they are

They're definitely a machine thread. However, if 5m/m is too small, and 6m/m is too big, they may be a "number" size - like a #10-24 or a #10-32 (probably a #10-24, coarse threads are easier to make.)

its torx #20 i think, i my be way off though.

I pulled some at the junkyard today, they are 5mm

I guess I had my screws mixed up or something