Hi overstress,
500kg in 396000kg is minor IMO.
The BEA would agree with you.
See accident report to Concorde July 2000, F-BTSC
https://www.bea.aero/uploads/tx_elyd...-sc000725a.pdf See Conclusion, 3.1 Findings:
"Taking into account the fuel not consumed during taxiing, the aircraft’s takeoff
weight in fact exceeded the maximum weight by about one ton. Any effect on
takeoff performance from this excess weight was negligible."