I believe they are the same, at least they are on all the cb750s I've worked on. Got to Partzilla, find the intake boots and look at the Related Fitment section to see what other models they fit.
Depends on what year of f top end the75,76 should be same outside diameter but the 77,78f2 top end have larger diameter spigots and use bigger boots...they also used the keyhole carbs that are larger diameter.