I think your carb is similar to my Murray. I remove the carb AND manifold as a complete assembly from the engine. 4 Star type bolts mount the manifold to the block. Then you can flip it over and remove the 2 bolts on bottom of the carb to remove it from manifold. You're correct, the 4 screws on top just hold the carb top cover on. I found it helpful to flip the carb over when removing the top as the float is hinged to the top cover and will be in more of a level position when turned over allowing it to slide out of carb body easier. Keep your work area clean and clear to insure you don't lose any small parts. I work in a copy paper case lid with raised sides to keep parts from rolling off. And be on the lookout for fuel draining out of carb when you flip it over. Good luck with your rebuild!

I work inside a large baking pan (bought my own at bargain store, no need to go to war with wife).
Baking pan keeps all parts from rolling away and any residual fuel can be mopped up with a paper towel.
Use your digital camera and shoot plenty of pix of every step you take during tear down, its better than a bread crumb trail when you go back together.