Silver metal tray with GANDAIS punch

Charming rectangular tray in silver metal, beautifully decorated with a Garland of leaves, flowers and shells embossed throughout the perimeter. At the rear, a punch indicates "10" (followed by a small unreadable character) then "GANDAIS", "ROYAL Palace", then two or three illegible characters and finally "B.A.". According to my few researches, it would be the master goldsmith Jacques Augustin Gandais, Goldsmith of the King, at the Palais Royal, received on October 10, 1834. But without any certainty. It is still solid, but presents the patina of time and intensive use: Front: stripes, stains, three small bumps and the silver layer is dimmed on the inner rounded edge of the 4 corners. I cleaned as much as possible the embossed patterns but perhaps a suitable treatment could do better. In the underside, the silver layer is very largely dimmed, leaving the metal "main" underneath, copper-coloured (brass? copper?), scratches, stains and various traces (it seems to me that there are even traces of molten metal!! what a life it has have!) . It measures 38.5 cm by 25 cm for a height of 1, 5cm. It weighs about 1.2 kg.