I think you would get coins all worth far less than the slabbing fee. Maybe a common silver
Roosevelt dime and two extremely common non-silver modern coins worth only a few bucks each would be my guess. With all the auctions on
ebay where it explicitly states what you are buying what attracts you to this. If they were valuable coins he would sell them individually. He's doing this to maximize profit, basically tricking people into buying worthless modern coins that he knows would bring next to nothing sold individually.