I can confirm that the 4 and 4S flex cable is not the same. Its reversed. Just bought 20 flex cables from china to a 4S and notest it the hard way. If you do a google search and find the diffrent cables and compare them you can also see that they are reversed. Might be old news, but thought i might add my answer anyway
If you wan't to replace the houseing, i would recomment to use this guide. http://www.youtube.com/watch?v=EHos6VNr_... In the comment under the video, there is a link to a picture of a screw chart, witch you can print and use. Saves alot of time.