Yep, I have a k75S and at 4,000rpm it was reading about 92km/h, that works out to 71mph at 5,000rpm
I don't think that means your speedo is accurate though. When I've checked speedos for accuracy, at readings of 100km/h, the actual speeds were usually about 96km/h.
Probably because I rode low revving cruisers before a brick, I also thought bricks should have a sixth gear, but now I appreciate the power and torque we get from them.