At this point there's no easy answer. If you have IPv6 you're on Arris, and if you don't you could be on Arris or Cisco. However in your case it looks like all of OR and WA was done with Cisco.
In my experience I go to my modem logs and get the mac address of the CMTS then put it in a mac address lookup website and that tells me the CMTS brand. Here is mine for example. »coffer.com/mac_find/?str ··· A1d%3Ace Cadant is the brand but was purchased by Arris.