First of all, in 1977 and '78, I was dating a girl who went to Fordham University in The Bronx and therefore passed through the Fordham Rd. subway station a lot, so this video has a certain nostalgic appeal to me.
The principal sample for Because I'm Me is from a 1959 Smithsonian Folkways anthology titled Street and Gangland Rhythms: Beats and Improvisations by Six Boys in Trouble, consisting of songs by 11- and 12-year-old boys from housing projects in New York, although you might not recognize the song at first as The Avalanches rearranged the sequence of lines from the original to fit their own composition.
The horn arrangements are from The Honey Cone's 1971 Want Ads. I know it says "1969" below, but that's when the album featuring Want Ads was first released - the single hit No. 1 in 1971 (trust me, I know, I was alive then).