Size for starters.
If it's small it's most likely CB.
Price.
Wild Caught is always best, and easy to spot. Big strong finlets, big head, size and a decent source.
Indo CB PBB are very easy to spot. They look low quality, and usually have bent up fin lets.
Big-In refuse to sell them anymore as they suspect one of the original parents was a Lapradei, the other a Turkana PBB passed on from Kamihata to outsource due to high demand in Asia (Mainly Indonesia and Singapore).
The first babies that were being sold from these breeders did indeed have a striking resemblence to Nigerian Laps.
PBB are not classed as "rare" anymore, so IMO there is no reason to but CB.
Even more so now that the last couple of years Kamihata have been mass producing them, giving up on their original F1 selective breeding program.
I guess its all about the $/¥...