Cloning in the restaurant business can be dicey, but the owners of Third Avenue institution P.J. Clarke's are having a go at it. Any day now they'll open P.J.'s on the Hudson at 4 World Financial Center. No word yet on an official opening date (two weeks ago, and again last week the word was "next week"). Despite the decrease in burger quality post-renovation, if this P.J.'s is anything like the original, the Financial District makes out well in this deal.