Well, it's pretty hard to recognize a voice from just "Hello" and "Who?" And as soon as I said he had the wrong number, I hung up. So if he recognized it then, it was too late.
It seemed odd because if he was calling for a customer, one would think he'd say "This is XX, from YY business." Yes, the company has his last name in it, but one would still say it. And one would ask for the customer by first and last name.
Maybe he wanted to have plausible deniability if he wanted to see how I'd react to his calling?
I know I'm overthinking it, and it really doesn't matter. I'm just going to have that surreal feeling for the rest of the day.