I presume one ticket DFW-BOM.

Under US law, the allowance for the marketing carrier of the first segment applies to the entire ticket. Sounds as though BA marketed the first segment, thus BA's allowance applies. It will apply to all segments, including the return or onward segments if there are any.

US law also requires that the e-ticket receipt show the allowance. It appears that you have that and that it is correct. That is what the check-in agent will see when you drop off the bags.