It is Apple's choice to accept it for repair or not. If they do, they must accept responsibility for it as a whole, including responsibility for previous repairs that may have been performed improperly:
i believe at some point my logic board was replaced ( because my serial number does not show in about this mac or the system report).
If your serial number does not appear, this would indicate an improper or unauthorized repair. Your logic board may have been replaced with one rejected by Apple for reasons unknown.