The hillbilly was actor Bill Mckinney who was born in Tennessee and served in the US Navy on a mine sweeper during the Korean war.  

He made lots of movies and was in 7 of them with Clint Eastwood.  He died of cancer in 2011 at age 80.

 

Yea, if I had been Ned, when my agent came to me with "Babe, have I found the perfect part for you"...I'd have fired them on the spot!