Could I use a iPhone 7 front cam on iPhone 8

On 2 topics a similair question is asked and the answer is simple NO.

I ordered 4 8 cameras but only one was full functioning, the rest had no Proximity.

Looking at my iphone 7 spare i saw the same flex with indentical number 821-xxxxx so i tried those 3 also. They also woked with the camera but not the Proximity.

Is it fair to say that the camera are identical (connector and specs) but that the internal wiring layout is different , thus not working proximity ?

And that this is also the reason why they sell iphone 8 frontflex with no sensors ? Because they are from a 7 ?