Sorry, parabellum, you are sadly mistaken.
Long before you joined, Singapore nationals could indeed join the airline younger than age 26, with a proviso that their national service was deferred for a period, until they reached age 33, at which point, it was considered duly served....and this policy had absolutely nothing to do with 744's, nor any other airplane in the fleet.
In fact, one local First Oficer who was terminated due to a duty time dispute prior to his 33rd birthday, promptly found himself back in the military service as his deferral was canceled when he no longer worked for the airline.
So, your stand alone statement
A Singaporean used not to be able to join the airline until he was twenty six!
is in error.