Lighter color, paint applied/not applied on right knee/wrist dart, various combos of this....
Think some of the other guys can give a better explanation on this than me though
Trilogo Fetts don't have a COO (Country of Origin) as well
They were released later than the original - although officially they were not all released on Trilogo cards so the name is actually wrong - I think there is a piece about them on Joe's site
the 4 knee/dart paint versions, there is a lighter brown belt version(s) & split vs single scar as well
http://theswca.com/index.php?action=disp_item&item_id=48167