It happens. Yet another reason you should test fire your guns before you carry them/take them hunting/etc.
In Texas last week Clint Smith talked about receiving "SHOT Show guns" from Smith and Wesson without firing pins. He got them out of the box, scooped up a bunch of ammo and went to shoot them off the back deck at his place in Oregon. *click, click, click*
My guess is that was a special order that should have gone to a 'smith for a custom job.
Actually, if you click through and look at the full set of pictures, it appears that the mags and slide/barrel assemblies are fine. It is just that that someone put the slide on a bare frame. Makes for one funky-looking gun.