Imac 27" 19,1 with replaces logic board

My logic board died and had to be replaced with one with an upgraded GPU - Radeon Pro 580X 8gb.

Originally after the repair at my local (non authorized) apple store, I had to correct the serial number but the modal identifier is now AAPJ1381,1 which is very odd.

The net-net is that I can not update to Monterey - I get the 'some firmware updates could not be installed' message. I have returned the system back to a fusion drive to see is the 'non apple ssd' issue was the problem, but now I simply think that I have a rogue or a mutt system. The original logic boar is toast.

Any thoughts on how to proceed? Can apple simply reprogram the logic board so that it is legitimate and can do updates. Any ides appreciated.