I'm not sure what exactly you are asking here. The filtered airbox from Van's can be used with either FI or carb. The carb installation has an extra opening for carb heat. FI doesn't need that, so it can be closed permanently. The carb installation also has a small bit of the airfilter cut out to fit the carb. You should be able to leave that alone. I've got the AFP set up on my O-320 and have lots of pictures
here. Even if you have to put on a new airbox, it should be able to be fitted up to your cowling without having to affect anything externally.