If there is no neutral present it is not particularly important which is the B phase since they are all ungrounded conductors and should be treated with the same respect. The only regard in line to line loads is phase rotation but you still need unique marking to identify the system they are connected to.
We do have in inconsistency between the code and industry practice. The code says the B phase of a center delta shall be orange but orange is also commonly used on 480 wye "BOY".
