I'm not calling shenanigans, and maybe this has already been addressed - it's late and after reading 5 pages I got tired ... however, why are the screen captures using Leopard? If the mini shipped with Snow Leopard, shouldn't that be what's in the screen captures? If, the system shipped with Leopard (which is entirely possible) the media would've been an upgrade and not a full install DVD.
It all looks believable enough and all, but something seems wrong.
If the hard drive was preloaded with Leopard and the Snow Leopard disk was packed by mistake, then those screenshots are what would happen if you inserted the Snow Leopard disk but had not yet installed it.
A less likely explanation is that he did upgrade but his old Aurora desktop was named something other than Aurora and so that preference was retained through the upgrade. That could happen if, before Leopard was released, he downloaded a leaked and renamed copy of the default Leopard desktop and used it ever since. (Happened to me, wondered why my desktop didn't upgrade and that was why.)