You don't have to open up your Xbox and look at the stamp on the mainboard to find out which revision you have. Using the manufacturing date on the bottom of the console you can easily determine which revision number you have.
Knowing which revision your Xbox is will help when installing some third-party modifications but maybe more importantly, determining if the clock capacitor needs to be replaced. Revisions 1.0 to 1.5 included a faulty capacitor that can potentially damage your Xbox. If your revision falls within that range, it's definitely something you're going to want to address.
If you flip your Xbox upside down you should see a sticker with a barcade, MFG Date, Serial No., etc. The MFG. DATE is what you'll be interested in.
Using the chart below, match your MFG Date in the range of dates in the first column.
|Manufacturer Date||Model Revision|
|2001 -> 2002-07||1.0|
|2002-08-18 -> 2003-01-25||1.1|
|2002-12-01 -> 2004-03-15||1.2|
|2003-03-02 -> 2003-07-26||1.3|
|2003-07-20 -> 2004-04-10||1.4, 1.5|
|2004-03-14 -> 2004-09-06||1.6|
|2004-09-13 -> 2005-08||1.6b|
Based on our example MFG Date of 2002-05-24, that puts our model revision in the 1.0 range. As far as that faulty Xbox clock capacitor that was mentioned earlier, this revision is of concern and we'll want to get it replaced sooner than later. If you have a 1.6 or later revision you wont need to worry about the clock capacitor.