You can find the NA 300ZX around in self-pull yards still. Prices vary but I just got some Toyota 4-piston calipers for $13 ea (no core charge!?) to upgrade my Z
Maybe they thought they were from a Z-car since I pulled other Z parts. Some yards charge more for a part if it is from a "truck"
New seals (rebuild kit) are only $6 per caliper.
I have also found info online about cross-drilled rotors ... stating it really doesn't help much with cooling but it looks good. hmmm ... ya, I also like the look regardless of what cooling it does or not. I buy them pre-drilled. I wouldn't do that myself. I also never go over 100mph so I think the cross-drilling is still more of a cosmetic thing.
Having internally vented brake rotors is the biggest upgrade for cooling vs the original solid rotors. (280Z)
I like the look of the Nissan calipers on your truck.