Should I wet sand after multiple stages of dry sanding?

I'm restoring/painting my 79 ford truck. I have got the whole truck down to bare metal but there's scratches you can see when the light hits it. I'm in the process of smoothing them out using 80 grit then 180 grit then 320 grit but I'm wondering if that's gunna be smooth enough and not show any scratches after my paint job is done. I'm also using bright baby blue if that makes a difference

You will NEVER got all the surface scratches out. The surface needs some "tooth" for the primer to stick too anyways. So just hit the bare metal with some metal prep and spray the primer/filler on it. Then lightly wet sand the primer with 400 grit followed by 600 grit. Any deep scratches in the primer can be filled with primer putty. If you have a lot of scratches you need another coat of primer. When you get the primer coat smooth enough that you're happy wipe it down with grease and wax remover and shoot your base color coat.