For Borderlands: The Pre - Sequel on the Xbox , a GameFAQs message board topic titled "When do you unlock the 3rd & 4th weapon slots?. Borderlands: The Pre - Sequel > General Discussions > Topic Details. Saica-Fox When you finish the AI quest you get a 3rd slot. #1. Croce. Hey guys, I'm level 19 in The Pre Sequel and somehow I don't have the other two slots. I joined my friends after work yesterday and they were. By the time I hit the 4th weapon slot unlock I was level 19 was all. You won't be able to vote or comment. Not sure about fourth. It makes taking any elemental weapon a bit limiting, because something will be immune to it. You're browsing the GameFAQs Message Boards as a guest. I have since got the fourth, i was level 18 but i was also underleveled for the area i got it in, people doing all side quests would probably be early 20s by that point. DirtyMick DirtyMick 2 years ago 8 OmenofFate posted We are all things Borderlands, including all DLC, sequels, pre-sequels, and re-pre-sequels. Slot machines are interactive objects introduced in Borderlands 2. Don't have an account?