Anna, Yes they are. I've physically tested an assembly from an iPhone 4 to my 4S and it works. ALL you need to do is replace the plastic bezel so it fits. One thing I did not test was the light sensor to see if it was compatible, but i will do that soon!
All of answers leave questions.. please be clear! Are the mounting tabs for the LCD and SCREEN the same as the iphone 4 (verizon and att) the same as the GSM and CDMA for iphone 4S? Excluding the bezel around the screen that closes in the phone to hold it together. this is different i know but its easily changed!
Thank you so much, recboot wasnt working until i clicked on Exit and thats the only one that opened up and it just kept rebooting the phone on and off im like uhhhhh so i disconnected and it started doing something i never saw before and boom it was restored lol. thank you! your the best btw:) i will try this on other broken phones stuck in recovery now :)