NW1,
"Max Cruise" was a nifty combination of Vmo = 530kts IAS, Mmo = M2.04 and Tmo = 127°C.
I should know, worked on it.
I know about the "cheating" on the Marilakes..... at some point recently there was a serious discussion about getting a few to work again so I went through the documentation. Unfortunately some of the digital protocols used seem to have been lost forever.
The Marilake never showed anything beyond M2.00.
And "my" Mach 2.03 was on a French Concorde.... no cheating Marilake, just a digital voltmeter calibrated in Mach straight from an ADC pot
As to the overspeed warnings, I'd have to dive into the doc, but I expect you're already quoting from doc, not memory, so no need to doubt your info.