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One picture means it has lion, right. Probably just has a more modern background.
 
That sounds sketchy. You would think the poster of the ad would know at least a few things about it while considering the unsupported operating system. Hell, he didn't even mention it was running Lion.
 
I'd say it's either a screenshot put on the screen, or he has an Intel Motherboard in there (either a real Mac's one, or a Hackintosh's one).
 
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