Swapping Motherboards from iCloud locked one to a working one?

Hi Guys.

OK I have just replaced the screen on my wife's Apple watch 42mm the only way i could get hold of a complete screen to swap over was to buy an iCloud locked watch & take the assembly out & swap them over it worked great.

I had another 42mm with the dull grey casing the iCloud one has a very smart bright silver casing with the milanese loop strap.

I tried the strap on the one i have but it doesn't look right I would like to swap the good non icloud locked motherboard across into the silver casing of the iCloud locked one.

Anyone tried this at all if so how did you do it

I know i need a small y screwdriver which i have ordered just waiting for out to arrive before i even touch it but just looking at it everything has to come out to get the board pout doesn't it?

Any help would be greatly appreciated

Thank you in advance