iPhone 4 home button compatible with iPod touch 4th gen?

I am looking to replace a cracked black digitizer with a white one. So obviously I need to buy a white home button as well. The thing is, I found an iPhone 4 home button on amazon for $1.99 with free shipping, and the iPod touch 4 home button is $6.99. Obviously I would like to purchase the $1.99 one, but I have never taken apart an iPhone so I don't know if there any any differences between the two. From the picture of the two I am looking at they look identical, but I can only see the front of the button and not the back. If anyone knows if these two buttons are in fact identical and I can purchase the home button for the iphone and use it on my itouch I'd really appreciate the information.