I have quite a few Yum Yums. I went through them and while the vast majority of the line drawings look like the Welch on the right, I did find one that resembles the one on the left.
It is a Fogarty. Most of the players have one line drawing pose, but this is a second line drawing pose for Fogarty (Leon's Welch is a second line drawing pose for him as well).
The toning is the key difference, perhaps due to a different quality of paper stock?