They do have the same face. Take two pics of them making the same facial expression and put them together. Their skin tone is alittle different, and the hair of course, but other than that it's the same. It's possible that Vergil's face may seem a surtain shape because of the skin color and the hair causing an optical illusion.
Thats probably why they made Vergil's hair fall apart in the first battle, to show that they were identical.
.....Ahem, excuse me for rambling, but thats just what I personaly think anyways. As for the manga, they don't look identical in the manga to me.