Hooks and "boxing gloves" will only be present on a tarantula as a mature male. I may be wrong, but I don't believe mature male Psalmopoeus even get hooks. However if yours is a male it'll be very obvious when it does mature, as the males become very drab in coloration and leggy. 3-4" would be pretty small to mature at for this species, though if male it could potentially be penultimate. Ventral sexing at this size is pretty reliable though, females have a very clear, wide furrow.