Actually, looking more closely, this is clearly a slightly later model than mine. The 3500 case was "borrowed" from one of Commodore's PCs at the time (possibly why there's that strange square bit on the frontplate next to the 3500 label - the PC badge would probably have fitted there), and mine has a backplate without any labels. It's actually nice to see them marked in something other than pen...
Oh, and mine has a blue motherboard, too. Different anti-corrosion, I guess.