It is the same unit across the whole model range, buy with confidence. I believe it needs to be activated and/or setup by the dealer in the firmware though so you might be as well getting a quote to get it fitted. It can also be switched on and off in the menu, that has caught a few people out.
Triumph quote 18 minutes labour time to fit the QS at the dealers on the Gen 4. I suspect any dealer is going to charge you at least one hours labour to fit and setup on a used bike. Good Luck!