The UFC said Monday that it had been approached by the fighters to request the change in weight class, which was subsequently approved by the Quebec athletic commission, the Regie des alcools, des courses et des jeux.
Lightweights can fight at up to 156 pounds in non-title bouts. It is 171 pounds for welterweights.
Stout, a native of London, Ont., has a record of 21-91. Noons is 11-6.