There is also a thread somewhere on the IB board where somebody used IB Avios to book an AA domestic ticket. It showed the "standard" luggage allowance for BA/IB, but at checkin there was no included luggage for non-elites because that's standard AA policy. That OP had no recourse for IB - acting essentially as a travel agent - showing an incorrect luggage allowance during booking.

In other words... sure... double and triple check the luggage allowance, but don't be surprised if BA-booked IB reward flights don't actually come with luggage - and you need to screenshot everything for a fight with BAC.