Bad day on the assembly line?

I've been in the process of restoring (rotisserie) an "un-molested" 1965 Barracuda. I've already replaced floor pans and the trunk well. During all of this, I'm amazed at some of the workmanship, or lack there of. The car has never been wrecked and has no body work done on it. I have found metal panels, stiffeners, etc., spot welded to nothing. Spot welds in a straight row, then one in the same row, clear over on the edge of the material. I have two 65 Barracudas, so I have the luxury of comparison. I've found brackets and clips welded in the same general location, but from a measurement stand point, as much as a 1/2 to 3/4 inch difference. Screws (factory) installed in one place on one car, but never installed on the other. Just wondering...is the result of "robotics," or someone having a bad day on the assembly line?
Norm

That was before cnc design ,and robotics . Just think how kick *** these cars would be if they made them now , w/ all the technology , and computer generation!