Haha, this would be a good starting point, however I suspect their situational awareness probably wasn't quite up the level required to notice what the overspeed was in knots/Mach.
I did see that note regarding the dual engine failure. This makes me think that the overspeed remains at 280 with the protections unmodified. So on the screen 235 will be the barbers pole but you could fly up to 280.
The aircraft does actually adjust the overspeed to 280kt with the gear down but you would very rarely see this as you usually have flap out by the time the gear comes down, and of course VFE is more limiting.
I did this in the sim while clean and then lowered the gear. The barbers pole came down to 280kts.