Pair of Chinese Cloisonne Ducks

Hello all! Hoping that my pictures are clear enough for someone to give me an idea of age. The lady I bought these from was a flight attendant in the 1970's thru 80's and she loved buying nice things from the Hong Kong markets. She said that either she bought them at that time or her mother who also loved going to the Hong Kong markets bought them but she can't remember.

The box they came in is beautiful but I'm not quite sure if it was original to the ducks. It's been suggested that they are for opium or incense. They are gold gilded and a magnet does not stick to them. Can't tell if copper or brass or other. A pair of ducks symbolize a long marriage.

Thanks for your input!