I ask because it's colored exactly the same as the End Round which I know is not played.
So do you place the portcullises as the ONLY event in Round 5 then move immediately to Round 6?
No, you play the full round. The color does not mean "don't play" it just means "something special happens" In this case, that "something special" is dropping the gates. At the end of the game it just means game over.
NO. p20 "The game ends when the Round Counter reaches the final space of the round counter track." The Round counter is moved at the start of each turn.... So, when it reaches the final space, the game is finished and the thieves convert their treasures in ducats... etc.