Buffalo WZR-600 vs HP-AG300H

I recently upgraded between major version 19 and 21. I believe in previous versions the 600dhp and ag300h models shared a single firmware.
My system says it's a 600dhp and the original packaging agrees. But when I do the lspci, the Atheros chips are on 00:11.0 and 00:12.0 like the 300 instead of 00:00.0 and 00:01.0. The HPAG300H fw installs fine.
I figured I would just post a note to the forum so anyone who is dealing with this can find an answer in the future. Look at the lspci and install the HP-AG300H fw if it matches.