4 years later I get my answer!!!

I'm not a knuckler!!!

One of our good friendly guys on this site faxed me an article written by Bill Hall in 1947 titled "Why cgs within an inch of the grip center is a good thing, and why I like wooden bowling balls"!

Just kidding!  An article from May of 2002 on thumb and finger wear title,

"How to read your hand"

In it he shows a bowler holding up his thumb, (like he pulled out a plumb!) and the back of the thumb is pointed at the bowler and the tip is pointing up!

In it he states that in this position if the right back of the knuckle is slightly worn for a lefty that is the "GOOD" thumb wear!  The wear and tear that indicates knuckling is located in the center of the thumb knucle joint!!!!
Oh yeah I almost forgot the righties.  If the left back of the thumb facing the bowler with the thumb tip up is slightly worn that ok just like the other side is hunky dory for the lefty!

Where have you been hiding this article Bill Hall!

REgards,

Luckylefty