I think the Bravo Company Manufacturing "subsidiary" is dedicated to the manufacture/selling of complete rifles.
https://shop.bravocompanymfg.com/default.asp
The Bravo Company USA segment of the company seems to be geared towards the manufacture/selling of components....though all Bravo Company components are named BCM, not BCU/BCUSA. It's likely that both complete rifles/lower assemblies are made on machines sitting next to machines making handguards, receiver extensions, etc.
It's common for the company to be called Bravo Company, but I never see it shortened to BC.