[Don W]

4x4s have 6 bolts on the wheels/hubs.

Nope, not all. Heavier duty trucks (3/4 ton and up) have 6 or 8, but most light duty trucks use 5 hole patterns.

[Paladin2]

Nope.

For the day GM 1/2 ton 4x4s used 6 bolts.

Blazers were only 1/2 ton.

6 lugs. QED

I have a number of ‘em.