What are the physical differences between an iPhone 4S and an iPhone 4? I'm wondering what physically has changed between the CDMA iPhone 4 / GSM iPhone 4 and the new iPhone 4S.


the placement or number of bands interrupting the metal side case
micro SIM slot location
camera and LED opening / placement
home button
receiver / front camera / proximity sensor placement


Superficially, the buttons on the 4S seem to align with the CDMA model spacing as opposed to the GSM spacing

I ask to know and for the practical application of people that want to reuse a precision case or protective film are going to find differences. I'm looking for first hand knowledge or reports of people taking a micrometer to the shipping hardware and doing a comparison.
The iFixit Teardown says that it has the same front panel (i.e. same positions for the Home button, LCD, sensors and earpiece). Other sites have also confirmed that it's the same layout as the CDMA iPhone 4.

It should work with any case made for the CDMA iPhone 4, and some of the less precise GSM iPhone 4 cases (i.e. ones with large cutouts around the buttons). It should also work with any Apple bumper purchased from January on, as those were designed to work with the GSM &amp; CDMA iPhone 4.

The 4S also has 4 symmetrically positioned black strips (gaps between the antenna segments), 2 on each side, just like the CDMA 4. It also has a GSM slot, which is pretty much the only distinguishing feature between the CDMA 4 and the 4S.