Simple answer... YES! Very much depends on the presentation. Most people fish mullet on a flounder rig or knocker rig of some sort. And you're moving this rig typically, so you want the mullet hooked in the mouth. If you tail hook him and drag him he will die very quickly. Same for a pinfish... you want to rig the same way. If you are just going to toss your pin out and leave him on the bottom a lot of guys will hook them in the belly. I tend to hook them in the back in front of the dorsal.