I suppose it depends upon your definition. The aircraft was certified for flap 15 landings to cover the abnormal cases - so the manufacturer probably considers it "normal" in the sense that the aircraft is certified to perform the manoeuvre.
Our Ops Manual had a passage that said something like "Flap positions certified for abnormal operations such as an enigne inop, shall not be used for normal line operations." This clarified things when coming across recomendations such as "use minimum flap when landing in gusty conditions."
[ 01 October 2001: Message edited by: Checkboard ]