Heres my 2 cents...I dont think there were any odds on a 1st round knockout or any round knockout for either fighter. Thats a prop bet and those are rare. When a fights fixed through the mob they will try to be as inconspicuous as possible and pressure bookies to abide by the Bets on either the Winner or the over/under on rounds only. The most they would do is allow a parley but absolutely no prop bets. This is why..If someone drops 100k on a first round knockout for Ali then that changes all of the odds and others will follow. Before you know it Ali is less of an underdog and closer to Even which pays out less. Its a red flag that the fix is in. But if your only allowed to bet on the over/under.. and for the sake of my theory lets say it was 5 1/2 rounds...Well then you can place a cool milli on the under, win and avoid any heat from the FBI or rival Mob organizations.
I'd give it a miss, I've learnt over the years that a good many champions were either protected or hyped and I'd rather go watch Contender Fights that may have propelled them to Title Matches. I'd rather go see Chuvalo and some others.
Good luck collecting. A similar scene played out in episode 1 of the Stephen King series on Hulu called "11.22.63"