So I just did that. I think, I have a little problem with the ROM field, I basically grabbed my hackintosh network interface MAC address and typed it without the ':' chars inside, and after it booted successfully (hurray!) it has problems authenticating with iCloud related services. I still have the old clover plist around, what's the proper field I should use for ROM in OC plist and what's the format it expects?
Edit: I've also noticed my TimeMachine thinks this mac is a new one. What have I messed up? Is this the fact that OC is iMacPro1,1 and my Clover config was iMac18,3? Do I need to generate some new Serial Number or SmUUID or Board Serial Number? I think one of them was important for iMessages?