Matthew, first you want to make sure your revolver is rated for +P ammo. If it is then you can shoot any variety you would like, standard pressure or the +P. Just keep in mind a steady diet of +P adds to the "wear and tear" on the handgun. If you're shooting it out of a .357 Magnum handgun, fire away all you want.

it is the same ammo to the same specs just some companies mark it +p and some don't the 38 super was made from the 38 APC ammo It was basically a 38ACP +p round (called 38 super) In 1974 the industry added the +P headstamp to the .38 Super to further distinguish it from the lower-pressure .38 ACP. Most current ammunition manufacturers label ammunition for the Super as .38 Super +P"

No Matthew. One can find 38 special that is not +P rated. Most you see in stores these days, though, is +P. Federal had (had - as in past tense - they've discontinued it) a .38 special round called "Nyclad". It was a hollow point round made of softer-than-usual lead and to prevent barrel leading they covered the bullet in a layer of nylon. The softer lead allowed the bullet to expand more than 'normal' hollow point bullets. It was actually fairly popular with .38 fans, but they too (.38 fans) began to dwindle, and Federal discontinued the round.

Matthew, no Sir. The +P rating is to signify that the pistol can readily handle +P loads. You can shoot the most cream puff of 38 Special loads no issue whatsoever. Also, in such short barrels, +P is going to give you a lot of increased muzzle blast/recoil that are disproportionate to actual velocity gains.

ALL 38 Super is +p ammo "In 1974 the industry added the +P headstamp to the .38 Super to further distinguish it from the lower-pressure .38 ACP. Most current ammunition manufacturers label ammunition for the Super as .38 Super +P"

No it can be standard factory target ammo. Common 38 special bullet weights are 125 grain to 158 grain. You can find plenty of +P or +P+ 38 special ammo for self defense purposes.