Homebutton assembly differences throughout iPad generations

Hi guys!

I was just wondering:

I know that the iPad 4 comes with a new flexcable which is easy to be damaged during the process of removing the touch assembly.

As far as I know, the assembly consists of:

-the physical homebutton

-the mounting bracket

-the hold-thingy which will be glued to the touch assembly

-the flex cable

Since the main difference is the new flex cable, my question is:

Are the other parts of the assembly the same/compatible throughout the generations 2,3 and 4?

So could I use the same physical homebutton in an iPad 4 aswell as in an iPad 2?

Same thing for the mounting bracket and the hold-thingy (sorry for the unprecise description, English is not my mother tongue)

Thanks for your help!

Regards from Germany,

Jonas