Even though Yello-boles were at the bottom of Kaywoodie's line the old briars are great smokers. Mine is one that is athestically pleasing and smokes wonderfully. Yeah there is a noticable fill but who cares.
Like others had said Kaywoodie had very high standards and purchaced the only best briar. A briar that wasn't worthy of the Kaywoodie name due to flaws got the Yello-Bole stamp.
This is true up until they began using Brylon.