it's a matter of using a court that actually does have those logos, then importing the proper textures to make it look like the court you want.
For example (I have not checked this to see if it is true), let's take the Jazz court because it has those logos in the correct position (again, I dont know if it does). You import the Knicks textures into the jazz court, and then using this tutorial
viewtopic.php?f=144&t=82793change the court colors to the knicks colors. it is a complicated and difficult process, but that is how you get those logos to show up properly.
It's not some simple "unlock" thing. Unfortunately, because of licensing issues, 2K cannot have the words "Madison Square Garden" anywhere in the game.