1963 Plymouth valiant problem!!!

Yep, and if you got lucky it's in the pan and the magnet can get it.
Just to be clear, he dropped the screw down inside the motor while changing the condenser?
Or dropped it down inside the distributor housing?

If it went in the motor look in the oil pump gear drive slot.
You might have got REALLY lucky. :D
I wish I had a pic of the distributor hole in talking about he was taking the little bolt for the condenser out and after he got it off there is a hole under the condenser and he thinks it fell in that hole. I need a pic I don't know how to post pics on here or I would to show you