It also looked similar to a Vietnam coin of that era, but nah.

1 Cash - Qianlong Boo-yuwan
https://en.numista.com/catalogue/pieces19755.html
weight: 3 grams (probably with the wear shown, it was 3.5 to 3.8 grams)
diameter: 23.2 mm (wear too, probably 23.5 mm)
metal: copper or bronze
other: square hole in center (5 mm x 5 mm)
Thanks for any help offered
M13