yes, the 4x4's do, all years 79-95.5
the 79-85 calipers are thinner because on the solid axle 4x4's they have a solid rotor.
on the 86-95.5 ifs 4x4's they have a wider caliper to accomodate a thicker vented type rotor.
you can use vented rotors from an 81-up landcruiser fj-60 on the 79-85 solid front axle trucks and then bolt on the calipers from the ifs trucks (86-95.5) for an improved braking system.
now the 88 or 89 (cant remember when the 3.0 v-6 was introduced) and up v6 ifs 4x4's use a larger caliper than the 4cyl 4x4s. supposedly they are a bit stronger calipers.
on the later model 4 runners (with the rear coil springs without abs) you can use the master cyl to beef up your brakes a bit also, it is a larger 1'' bore and can move more volume. i believe the one im using was from a 94 4 runner v6 w/o abs. that is on an 84 sfa 4x4 though, you may have a different setup.
if your really looking for a bad ass setup check with downey off road , all pro off road or skys manufacturing for a rear disc brake conversion...