Yea, the TBI cars/trucks came with the same round air cleaner back then. Hell even my '94 chevy truck had the black round air cleaner and it had the 5.7 tb(toilet bowl) injection on it.

 

A TBI setup looks very similar to a carburator.

I had an 86 Regal that was TBI.

Take closeups without the cover.

 

The 1984-1988 Monte Carlo SS had a 4 barrel carb(Rochester I believe) from the factory.The 6 cylinder LS models did have fuel injection according to my literature.

 

My ‘87 had a 2 barrel Rochester carb. There were many choices at the dealer when ordering them new back then. It could be a 2 or 4 barrel carb Rochester or Holley. Or it could be TBI. The 305 in the cars and trucks had the same block and heads but different intakes. The intake on the cars were meant for fuel mileage where the truck was for low end torque (not that it made much or was much different).

Carbed or TBI it makes around 145-150 at the wheels stock.
i can’t see any of the pics you’ve posted or I’d tell you exactly what you’ve got with the air cleaner off. But they all used the same air cleaner can. One way of determining what it’s got is a carb car still has the mechanical fuel pump on the passenger side of the block I believe and the TBI will have an electric pump in the tank like the generations after it.