No, I haven't taken a stroll or found arrowheads or anything like that. I worked there from 1996-1998. As I said, there are some buildings that go back to the beginning of the 19th century. It was all dutch farmland back then. Very likely there were natives in the area, but I don't know anything about where you would find artifacts.
If you haven't looked already, here is the "official" history -
http://www.wyckoff-nj.com/aboutWyckoff.html
You may also find some assistance through the bergen county historical society.
http://www.bergencountyhistory.org/
They have some things in the steuben house in river edge that pre date the revolution - unfortunately, they are right on the banks of the hackensack river, and some artifacts were seriously damaged with the flooding.