No , s/he means a King BaboonHonestly, i'm not familiar with this species. I tried to Google 'KBB,' but all that it brought me was 'Kelley Blue Book' and 'Kitchen and Bath Business.' No Ts there.
I'm being silly (though, i really DID Google it).
I'm assuming you mean the GBB (Greenbottle Blue, or Chromatopelma cyaneopubescens)? I'm learning about this one as i go- my sling is currently at about 3.5", and is still in the gangly teenage phase. My GUESS would be that they thicken up closer to being mature adults?
Sorry, endoflove, i'd never seen that abbreviation used before. Nor do i have any experience with King Baboons, so....i'm not really being helpful on any level, lol. Hope you find your answer.lol sorry i mean Kbb as King baboon