Off topic but a helpful and efficient ex-housewife did the same to my piles of linotype and #2 alloy ingots. I had melted some 25 lb pigs of linotype into Lyman ingots and had also mixed up abut 30-40 pounds of #2 alloy poured into the same Lyman ingot molds. You couldn't tell them apart by looks. In hindsight I should have marked them somehow, but had piled them on opposite sides of the garage to keep them separate. Came home one day to find a newly clean garage with one big pile of ingots all mixed together. "Oh, that other pile was in the way so I just moved them all to one place." Need a facepalm icon here...
I've noticed that harder alloys sound a little different when dropped on concrete. The harder alloys seem to "ring" at a higher pitch. I dunno if there would be enough difference between your two alloys, but you might give it a try.
