The staff at Central knows how to handle every request... and yes, it's like a candy store. And luck has a lot to do with the used gear offerings; sometimes they're slim, then, they have plenty of interesting stuff. Often, I've seen cameras or lenses there that I never had seen elsewhere other than eBay. Then, there's the find, like a Konica Hexar with fixed lens they had for sale once... Or some nice Nikon RF cameras...
They go nuts on some items, both ways high and low. I saw once or twice neat Leica M2 selling for just $600, with a nice warranty for used equipment (either 6 months or 1 year). There was once a 135mm Nikon RF lens for $400 too! I never tried bargaining there, though... they made offers on my cameras, but I know they were joking (I had a Leica M5 once; they offered a deal for it if I got an M4).
Definitely go, buy film from them, something... I usually do that: film, camera straps, something. They do have the tourism trade: visitors that come and buy digital P&S too.