If you still have the stock carbs, they should have a stamp on the side PD 46 A (or C).
These are mechanical slide carbs, not CV type. No CB550 SOHC4 came from Honda with CV carbs.
These carbs will "run" without the air box. But not well, without changes to fuel metering within the carbs. The filter change may be cosmetic to you, but it is not to the engine.
The carbs had "lean burn" settings with the stock air box AND the exhaust, that were both matched to the engine needs. Changing either of these items will demand alterations to the carbs, as they will run even leaner, to the detriment of performance and engine health.
To witt: The idle circuits will be too lean. The slow jet is smaller than the 78 model (#38 vs #42), though the float height is higher. It may be possible to compensate with other than stock settings of the Idle Mixture screws. As this bike has no accelerator pump, this setting will determine how well the bike responds for low RPM with a simple throttle twist. If too lean, the bike will stumble when you grab a handfull of throttle.
You will likely have to change the main slide needle height to compensate for the loss of carb throat vacuum (effect 1/4 to 3/4 throttle positions), and the main jet will have to be increased above the stock #90, again to compensate for the exhaust and air filter changes. It's possible, that to get it running really well at all throttle positions that the needle taper would need changing, too.
If you are willing to commit to the many hours and recursive testing needed to re-tune your carbs properly for the cosmetic changes you desire, then proceed, as it will be quite a learning experience for you. But, this is NOT a simple parts swap endeavor. You will need a test track or dyno sessions to get the carbs sorted to your proposed changes.
I'd like to know what your plans are for the finished bike. If simply a show piece, you can probably use the carbs as is. If you also want street performance on twisty/winding roads, then carb details need to be addressed.
Cheers,
