I was just thinking. It's a wall painting, It's deteriorated over the centuries, and has been repaired a number of times.
My point being that the faces are no longer what Da Vinci created.
From Wiki:
This restoration [most recent] took 21 years and on May 28, 1999 the painting was put back on display, ... When it was unveiled, considerable controversy was aroused by the dramatic changes in colours, tones, and even some facial shapes.
You're quite right about that. Undoubtedly some fine detail has been lost and altered. Even the original wasn't exactly a photograph that facial recognition software could pull an accurate identity out of.
But an 'expert' could. /s lol
Good find from Wiki!
I found it amusing that DaVinci might have to use his own face for lack of subjects. He was considered a prolific artist in a place and time of prolific artists. Also, the Last Supper was painted on a wall in a monastery where there were many men who would have had at least some time to sit for a sketch and would have been glad to assist the Maestro in a noble project done primarily for their benefit.