I don't believe Oldham buses would ever have been seen here on the 14 as they always worked the other way round, however, it's difficult to say that it 'never' happened. The last surviving PD1/3 246 is in Uppermill square on 11th October 1969 during the Ribble Enthusiasts Club tour which appears a few times in the "Saddleworth Buses" gallery.
From an original slide in the David Beilby collection, photographer unknown