"tip"= "leave" > "dip"= "leave" ?

[Sam Clements]

While working on an article about the origin of the word faggot, I read Barry Popik's contribution of words from "The New York Spy(1967).  In a section on "the Gay World", a listing of terms is included that are in use in the community at the time.  

The quote was <Tip (verb) --to leave.  ("We must tip now.")>

Since my son Zack is 12, and currently emulates Rap culture, I have heard him saying for a least the last two years "See ya, Dad.  We're gonna 'dip.' "  I know he means that he and his friends are leaving.  

RHDAS cites "dip" meaning to leave in a 1903 quote.  The next cite is from 1984 [Toop, Rap Attack:  Dip, or buff; terms for leaving.]  He allows as how the 1984 quote is perhaps an independent coinage.  (And I agree).

My question is:  Could the use of "tip" meaning to leave have been in use enough in NYC in the 1960's, possibly in the homosexual community, but the African-American Rap community picked it up and mangled it to "dip"?

It's not hard to believe that ANYONE hearing the phrase "Let's TIP" could have heard "Let's DIP."

I'm sure that if I were a linguist, I could have written my question in less space and more succinctly.  Sorry.

SC