Certain Model Number for Touch Screen?

Hello everyone,

I recently bought a Ipod Touch 2nd Gen off ebay that needed a digitizer. I first thought that any 2nd gen digitizer would fit into any 2nd gen ipod touch. Then I find out that I need a certain model number to get the ipod touch to respond to the touch screen. I have tried the 821-0627-03 and 04 models but it did not work. Anyone know where I can find 821-0627-A at a cheap price?

Thanks