Project Farm has some really interesting You Tube videos with slow motion lawn mower carb atomization clearly shown.
All 4 stroke engines produce a strong standing wave pulse in the intake runner at certain RPM's, depending on factors like cam timing, cam overlap, intake runner length, volume and RPM. Engines that have one "carb" per cylinder are subject to some reversion (back flow) through the carb (that entrains a bit more fuel) and often produce a cloud of vapor sometimes called "stand off". You can clearly see it in the video below.
In the case of the engine in the video, they would be far better off to use a single large air filter box to contain the cloud of fuel vapor, as this controls the Air/Fuel mixture much more accurately.
Those old engines really do need the air filter assembly to be installed to contain this vapor.
But to answer your question directly, a more modern carb, if chosen correctly, will give a better result. But it will not offset the issues created by poor cam timing, poor intake valve sealing and obvious issues created by a very low compression ratio.