If it were my reloads I would disassemble all 1,000. Recover what I can and figure out how to absolutely prevent that mistake in the future.
If I made a mistake on "two" that I realized later, then I could have made other mistakes and not realized them. Under no conditions should anyone shoot any of those shells.
Cannot imagine how he realized the mistake after the fact and that it was exactly two. At least he notified you.
"The ultimate authority ... resides in the people alone. ... The advantage of being armed, which the Americans possess over the people of almost every other nation ... forms a barrier against the enterprises of ambition."
- James Madison