The one with 3 marks is probably a "modified"...choke.
The one with 4 marks is probably an "Improved Cyclinder" ...choke.
Screw the chokes out of the barrels...they're probably marked on the bodies of the choke tubes as well.
Since you bought the gun used....you need to remove the chokes make sure they're clean ...and that the threads on the choke tubes and inside the barrel are clean and properly lubed. They should run in and out of the barrel...with just finger pressure ( put a finger inside them to spin them in or out )....you should not need a choke tube wrench to remove them or to put them back in.
Then you need to clean the cokes every time you shoot the gun / and the threads inside the barrel too.