turn the key on, bump the starter( dont start the truck) and hop out, you should hear a slight hum from either the engine bay or the fuel tank....thats the easiest way to tell with out crawling around under your truck
my truck had both, just the one on the block wasnt hooked up. i guess dodge didnt feel like taking it of or something.if the pump is under the hood then it's not in the tank...lol....IMO--if you have the money...get a system...if not, then just the pump, like i had to do a few yrs ago...