What is Glen Ross?
OK, I get that Glengarry are the new leads.
What is Glen Ross?
I have a theory: The real estate developments are all called "Glen [something]." So Glen Ross might be the land they're now supposed to sell with the "weak" leads. Glengarry is a new development with the supposed better leads.
I'd bet the leads aren't any less weak, they just tell the salesmen the leads are "gold" so they'll sell more of the left-overs from the current project in order to get onto the newer one.
Anyone have a better theory?