If footage doesn't convince you either way, then you should assume that it's legit. You only question it because it's Carnera.
That's not true. It is normally assumed that the people who fixed it were mostly in Carnera's camp anyway. Watched it hundreds of times. Certainly looks like Carnera's fist did not connect with Sharkey's chin. Certainly looks like Sharkey's forearm connected with Sharkey, but not necessarily his chin. Also it looks like the uppercut was thrown exactly in the way the wrestlers describe their "European uppercut" with the 'punch' turning into a bent-arm body-check before contact.
I don't assume anything's legit unless I'm 100% convinced. There are lots of KOs that are questionable.
For a start, this "punch" very possibly wasn't a FIST at all, and was in fact a FOREARM. Which alone should be cause for considering it unusual.
But Carnera's people had tried all that before, with Primo hitting people normally with his gloved fists, with opponents flopping to the canvas, and it did little for Carnera's legitimacy or reputation as a puncher. This forearm "European uppercut" seems to have been more convincing, and has a majority of this forum convinced almost 90 years later. My point being, it could be fake. The footage certainly doesn't show a normal punch, it shows something that might well be a forearm strike of some sort.
Nah. It's obscured because of the angle, but the fist is definitely in position to catch Sharkey on the chin as he's bent over.
I watched this repeatedly in the slowest speed. That second hook definitely catches Sharkey, and he hit his head on the ropes whilst falling. Even if the uppercut was somehow fake, that hook wasn't, and I wouldn't be surprised if that was the shot that did it.
A fixed heavyweight tile fight is not like some glorified WWF bout. It is a serious criminal undertaking. You let as few people in on it as possible, for the same reasons that you do this with an armed robbery. Three people can keep a secret as long as two of them are dead. If Carnera didn't need to know, then you wouldn't tell him, because then you are potentially letting his trainer, family, spit bucket carrier in on the secret. Fixed fights are planned by small circles of people, there is no choreography, and the script is kept a simple as possible i.e. KO1!