MPEP 2144.04(VI)(C) cites Chicago Rawhide, 223 USPQ 351 (Bd. Pat App. & Inter. 1984) for both "[t]he mere fact that a worker in the art could rearrange the parts of the reference device to meet the terms of the claims on appeal is not by itself sufficient to support a finding of obviousness" and "[t]he prior art must provide a motivation or reason for the worker in the art, without the benefit of the appellant's specification, to make the necessary changes in the reference device."
The latter part of the quotation should be removed from the guidance.
Chicago Rawhide predates KSR v. Teleflex, 550 US 398 (2007). In KSR, the Supreme Court has prohibited the use of TSM as a "rigid and mandatory formula" of motivation. KSR at 401-02.