It does not help too that Apple's modeling number system is a joke. MacTracker shows 5 "models".

700/800mhz April 2002-May 2003

800/1000mhz May 2003-Oct 2003

1000mhz Oct 2003-April 2004

1000mhz/1250mhz April 2004-May 2005

1420mhz May 2005-Oct 2005

So three 1ghz versions out there maybe? And even your chart shows two if you look, one being education.

But I really miss the days of simple model numbers. No all this EMC stuff and "order" numbers like M8577LL/A.   I know order numbers are nothing new, but you almost need it now to know what the heck you have.