He seems to have a little yellowing down the sides and underneath. Us west coast herpers back in the 80's used to rate desert cal kings by how little yellow down the sides and underneath they were. The higher white, the better the snake. The best wildcaught high white cal kings you will find, have yellow down the sides and on the underbelly. Today its only the captive bred "generic" desert cal kings that have zero yellowing.
Maybe through the interests you have awakened among eastern king enthusiasts, selective breeding will take place and eliminate the yellow and produce some all black and white easterns.