???? ????? – ????? ????? ?????
note his first words in that section: “minhag avoteinu vadai hu torah” so this seems to predate his writing it.
the apter rebbe died in 1825. the book was not published until 1863.
i’m not saying i’m for or against it, but this is the oldest reference to the minhag that i could find.
http://www.hebrewbooks.org/pdfpager.aspx?req=20974&st&pgnum=183