The rectifier section will work fine. Not so sure about the regulator section is plug and play.
The CB750's field coil grounds one side of the field coil and powers the other.
The DOHC4's regulator provides both power and return to the rotor.
Given the data I found below, I'd be dubious of success claims and suspect the regulator may be damaged unless mods to the SOHC4 alternator field coil is also made.
Perhaps there is a credible reason why the CB750 SOHC4 isn't on the advertiser's fitment list?