It may not be 'real,' but I wouldn't count on that being a fact.
I see what you're saying ... but the video methods are so different. Azzam looks like he's in a studio - a tape so different from the others; OBL looks like he's hiding in a bunker. It just strikes me as odd - but by no means am I discounting Azzam's tape.
I'll repeat my new mantra: Death to all terrorists!!
What if Azzam and the other al qaeda cell members -- made up of American whitebreads and ME illegals -- are here within the U.S.? What if the tape was produced inside a studio? What if they are awaiting the hit?
These are all just what-ifs, of course.