At MCO, there are 2 sides of the main terminal (A and B) and there are rental car garages on both sides of the terminal. But during COVID, basically only the A side garage is open.
When you rent a car from
Alamo and elect to skip the desk and/or kiosk by doing all check in ahead of time, you go directly to the garage and find the aisle of the car type you have booked. You then are free to select any car in that aisle, get in, and drive it out. The booth at the exit of the garage will finalize your reservation and give you the rental agreement. So if you booked a full-size car, you would go to the full size aisle and pick whichever car there you liked.