Fog light nut size 2001 AC steel bumper

Anybody know what size nuts these take? I've got a couple that have rusted enough that I'll never get a wrench on them and I'd like to replace with stainless steel anyway.

 

If they’re small enough they’ll come off with propane heat, unless of course, it’s touching something plastic, then forget my comment. I had to remove the small screws holding the front chrome bumper to the bracket that way.

 

The body of the fog light is plastic. Not worried about getting them of. Need the size so I can get new nuts.

 

M6×1.0

98% sure, but it's been several years since I've installed foglights on my chrome bumper.

 

^^^ can confirm ^^^

 

Thanks guys.