Do you have a source for this? It would be interesting to know more about their refurbished devices, I've purchased multiple in the past and they've always been identical to new.Logic board, display, and all other components are salvaged from other devices.
Board level component repairs for liquid damage is performed, but the board will never be as reliable as new. This is because materials like epoxy underfill, which help keep the chips in place, are never replaced.