Generally, the answer is "no". We're probably smaller than you think -- only about 30 Most of us in NY and halfthe people working out of thoseNew York are sales people who cannot be interrupted or we will run out of money and have to stop sending out so many free t-shirts. We don't really have anyone whose job it is to show people around the office.
With that said, you can always try sending an email. If someone in the office recognizes you from the site and feels like showing you around we can try to set something up.
Also, definitely don't try to "just stop by" -- building security won't let you in (that's kind of their job).