Your Friend Is Right
It is against the law to build a pistol from an action already designated as a rifle. There are a couple of custom receivers out there you can build one from because there not yet designated as either a rifle or a pistol. The easiest way to build one is to buy an XP or Striker in a caliber you might want or have a gunsmith re-barrel or customize it. There is a guy(358hammer) over at Specialty Pistols that that uses undesignated Savage receivers and is building rear and center grips (I think) pistols from them.
Good Luck In Whatever You Decide