Would I be correct in saying the PS3's with a chromed strip will play PS2 games, and those with a matt silver strip won't? As far as the UK is concerned, at least? I have a launch 60gb, as do a group of my friends who went threes on a console, but my brother has a 40gb (which as far as I know is the first non-PS2 compatible PS3 released here), and apart from the lack of two USB ports, the card readers and a LOT of heat, the only other (and most obvious) clue to tell our PS3's apart is the silver strip; Mine is chromed, his is not.
As far as I was aware there was only ever the 60gb then 40gb released here, I've never seen or heard of anyone with anything different, except for those with DIY HDD upgrades of course, and in America I thought there were the 20, 60 and 80gb that play PS2 games, then the 40 and 80gb that don't, surely the USB ports and silver strip differences are the same?
Therefore, the clue should be whether or not your PS3 has a shiny silver strip or not... Of course, this is just me speculating from my experience of UK consoles so I don't really know; just trying to help (before anyone jumps down my throat for it!)