Willard Mullin's First Published Drawings?

Here is a real treat. In the past I featured school yearbooks from Dodger greats Sandy Koufax and Jackie Robinson, here and here. Now I have something totally different. I recently ran into a yearbook of a man known more for creating a beloved Dodger icon. Here is a yearbook from noted sports cartoonist Willard Mullin. Better yet, it has several drawings of his within it; possibly his first published works.

Above is his portrait photo with the title "cartoons" underneath. He was on the Senior B Art Staff, and lent his pen to the effort in making a perfect yearbook for his class. Check out several of his drawings below.
Notice the artist signature at the bottom of each drawing. It is very similar to the signature he eventually used as a professional cartoonist.

(Auction Link)