Yes, BA1544 code shared on AA metal from LHR to ORD booked on BA ticket stock 125-
I don't have an eTicket receipt as it is booked through our corporate TA.
I also have a connecting flight on an AA flight, on AA metal (no code share, but all one ticket) on to ATW.
The agent did say to me when it was booked that it was a through ticket so my allowance will count for both flights. I took that to mean the 2 bag allowance, but not sure about the weight. Not much info on BA.com.