They may actually have thought they were getting the better end of the deal -- those Barber quarters are probably significantly underweight at that level of wear, so their literal "melt value" would be less than that of, say, 1964 Washington quarters. I still think you got the better end of the deal. If I'd seen a lot like that at that price, I would've bought it, too.
That's what I thought when I looked at it under a loupe. Can't believe they could solder such a tiny spot.
The one cool thing with the Barbers is that you have four possible mints with them, including New Orleans up to 1909. And I have found an '09-O in a junk purchase.
Used to be a piece of jewelry. Looks like solder. Copper/nickel is relatively easy to solder to, unlike silver.