I wonder how stocked the Supreme Store in New York normally is.
Depends on when you go, but in general: not very.
There's always a line when new stuff drops, so the hyped stuff is gone immediately. The rest slowly goes over the next few days/week. They do re-stock from time to time as well though.
When I was there in the summer, pretty much all Supreme tee's were non-existant except for a couple on the sale rack. Not a single fitted in my size, though quite a few larger sizes (no box caps or logo caps though).
If you were going to go to NY and Supreme was a priority for you; plan you timing wisely or else you could very well be out of luck. It's not unlike the Supreme situation at Nomad even at the Supreme store itself.