NEED SOME HELP ON A BULLETIN

Hey guys. I am in need of a BCM part number 19187514. In the engineering notes it says to access GCUS-9-4131 or GMP 2019-146R. I cannot find these anywhere. I have tried SI and search in Dealer connect even went to EPIC and searched to no avail. I am sure that I need to send it somewhere. I have tried calling a couple of the suppliers we have used for our cues and radios, but with no success. I had my FOP look because he was the Parts Manager before me and he too is at a lose. I need help.