Mahmoud or not?

It's pretty close. The nose and eyes are very similar, especially the nose. But not everything appears the same.

Mahmoud seems to have a thinner beard under his lips and on his chin than the mystery man. This conclusion is based on all the publicly available photos. The comparison photo did not make it readily discernable due to his hand. Admittedly it could be a function of lighting or beard trimming, but I'm leaning against based on this one.

Their head shapes look different. From this shot it appears that mystery man's is more pointed than A'jad's. This could be a function of camera angle, but it would help if Mahmoud's hair didn't fade into the black background on the left. Here's another pose without the black background, but with a less than ideal angle:

Finally, from general appearances this person appears to be a grunt. As the Russian story suggests, his gun was not the same type carried by most students. Mahmoud is an intellectual and would have probably spent most of his time with the crowd of planners and thinkers. But, since it's possible he was just out for a break it's hard to accept this line of thought as conclusive evidence either way.

All things considered I don't think it's him. Maybe just Russian disinformation or an attempt to stir things up before Bush's Asian summit. Wonder if the prez asked Putey about it on his stopover in Moscow today? Or maybe he already knows. He knows a lot of things he can't say.