@daneoni thx 4 ur fast reply, so u mean the serial number (w87*****XAH) should be changed with the logicboard replacement ? .. if so i still have the same old serial number.
What i meant was sometimes technicians forget to re-encode serial numbers to replacement boards (yours remembered) which could be a telltale sign. In your case you're gonna have to assume they did based on the genius receipt saying so