Ahh sorry I forgot I'm using the Twilio ekata_reverse_phone addon that you can get in twilio marketplace so I have carrier info in the lookup response.
I guess then whether it is 100% on Twilio being the carrier is a little less likely but I tested a few more twilio numbers I know and they all returned with Twilio as carrier.
{"mobile_country_code":null,"mobile_network_code":null,"name":null,"type":null,"error_code":60600}