iPad (1) model identifier numbers

[MorrisTheCat]

What I really need, and this will be of help to others, is a reference or list of model numbers and a good procedure to properly identify any iPad's specification i.e. From it being a true 64GB to say a 16GB 3G able to work on GPS or not WiFi or not etc. With so many second hand first generation iPads on the market I have already found one that the owner advertised as being the top model. Going by the reaction when I said it wasn't what he advertised it as he was not very happy. I suspect he was out to make some easy money off an unsuspecting fool...

I have found that my needs on the iPad have grown and with the warning of low memory constantly appearing in some apps I need a higher spec unit. I don't believe the iPad 2 is needed yet though.