Not very likely to have that low of a difference on a commercial aircraft.
U-2 was something close to that, but back of my memory recalls reading 10 kts, but then that is a military aircraft try to get absolute max altitude.
Big difference than a commercial aircraft using a 1.2 or 1.3 g stall margin so you can actually bank to turn on an airway.
I guess I didn't pay that much attention, and I don't do it too often, but at FMC calculated max altitude in B744, you have well over 20kts between overspeed and stick shaker (probably closer to 30), so I image in the B742 is similar.