I invite you to peruse any dedicated sports bike forum (R1, Honda, Kawasaki, etc), and notice the not insignificant number of "What's your top speed?" posts which go on to discuss how the speedo's stop at 186mph while the revs keep on climbing.
What you describe may be true for the odd model (eg. some newer Suzuki's when in 6th gear only), but it is not commonplace nor uniformally implemented. The vast majority of UJM sports bikes just have speedo's that merely stop at an indicated 186mph (or 299kph) while the revs keep climbing.