Street Slam is the US title, with the regional US teams, while Street Hoop is the non-North American English version, with the global teams. Or would it be the non-USA/Canada English version? Not sure what it's called in Mexico & Central America.
I got this game last week and noticed exactly this. I have the MVS chip and so when I set it to US MVS I get Street Slam as a title screen and when you play the game you play cities around the US. If I move the switch and play as if my NEO was just a US model the title screen say Street Hoop and you play countries around the world.