"What number is this, chap?"
"SEVEN-A."
"OK, man, don't get excited ... It's cuz I'm short, I know."
What you have above is the way it was done on the TV show (they walk up to an apartment door, "7-A", har har). But on the record he's saying "what number is this, Chip?" (as in producer Chip Douglas). And he's "sure", not "short".