I didn't really consider they may been sent back to the factory but I wouldn't doubt it with this one. It was done expertly and may even work better than one in it's original state. Of course they likely didn't have our sentimentality for the original condition in those days.
I remember my sister-in-law throwing away all her vinyl when CDs came out. My son's head exploded when I told him that but that was just how some people thought then: out with the old and in with the new latest, greatest.