I've done a number of shoots for Kink (pun intended) including one just this past Monday in a bar. Yes, the "blue pills" provide help but over the course of a 5-hour shoot there is a need for fluffing despite the chemical assistance. There are no official fluffers on the set, but there is quite a bit of fluffing between cast members between takes. In the last one there was one guy who was particularly into sucking dick and volunteered to be a fluffer. In fact, sucking got him hard so in providing fluffer services he was able to get "fluffed" himself. It's a win-win if there ever was one :-)
As for the tours of the Armory, I'd highly recommend it. The place is amazing in it's own right as a piece of historical architecture, and the overlay of the porn studio makes it even more intriguing. Should be on every gay man's list of attractions when visiting SF!