I downloaded a speedometer app and checked the CB speedo today to answer my question. Spot on. So yes, these people are commonly running 75 to 80 mph on a freeway marked 65mph.
It's nice to have an accurate speedo. I also checked my old '76 Guzzi 850 T3: 10 mph fast across the board. '02 Guzzi California EV: 5 to 7mph fast. (both cable driven from the tranny)