As far as I know that's a Negative. Pretty sure they are different and even the drive sleds are apparently also non compatible between pre-4,1's and post 3,1's, as noted by the requirements of this drive sled here (which I have for my 5,1 and is superb for SSD mounting) -
I remember reading that someone took their beat up 5,1 Pro to the Apple Store and they paid a very reasonable amount to get everything professionally transferred over - including serial sticker and all - to a new case. Not sure if that's still doable or what the specifics were of that particular situation, but maybe worth a look?
4,1 and 5,1 have nearly the same hardware, but other SMC firmware. Thats why you should not mix backplane board and processor board between 4,1 and 5,1. Otherwise it will result in maximum fan speeds.
4,1 and 5,1 have nearly the same hardware, but other SMC firmware. Thats why you should not mix backplane board and processor board between 4,1 and 5,1. Otherwise it will result in maximum fan speeds.