I called the 402 593 5445 number and got pushback from agents about doing a BRG on a non-refundable rate without having already booked it through Hyatt first, which I obviously don't wanna do if they later don't match my rate since it's a non-refundable rate.

EDIT: Finally found an agent willing to do it without having a Hyatt confirmation. Or two agents were but got disconnected from the first one who was having trouble locating the rate anyway. The second agent who did it at first refused to do it but was willing as an exception when I told her a previous agent was already helping me.

And they did match Traveluro.