Thumb on extend a boom?

[763bobcat]

I have a Bobcat 331E(extend a boom) and would like to add a thumb has anyone seen one with a thumb? I would think as long as the boom is retracted and the locking pin is in, I could weld a mounting plate to the non-extendable part of the boom and it would work fine, just looking for any input/advice.

 

[Cataclysm]

My CAT 420D Operators manual says no thumbs on the xbooms.