Ball Gunner? Yes some had a ventral gun, and it was retractable to try and cut drag at cruising speed.
B-25B dropped the tail gunner to add the dorsal and ventral guns.
Some B-25's shown with dorsal turret and tail guns, but no ventral turret.
Most B-25's shown with a 50 mount on each flank. Various numbers of .50's at the nose as well.
Part of the reason I started the "version" thread, I wanted to see how many different version of each plane still in the running was the one folks wanted to be added.