Good question. Of course there are many ancient records written on metal from the period and geographical location. Here are just a few. Google is a good place to start if you want to find more.
The golden plate on the left is written in Phoenician, while the lamina on the right is written in Etruscan. (Rome, Museo Nazionale di Villa Giulia)
This rare bronze tablet, the oldest to be recovered from the ancient Near East, dates to the middle of the thirteenth century BC. The tablet captures in bronze the treaty of a Hittite king with a vassal in the south. Metal tablets were created for special occasions, although very few have survived into the present day. Because of the value of the metal, most such tablets were melted down and reused over the centuries.
A pair of bronze plates dating from the second century A.D.
There are many many more... Also look up metal scrolls, the kinds that were buried with the dead seas scrolls. Silver and lead I think. Records were kept on metal when the content was too valuable to be lost with deterioration.
Hmmmm...
NONE that had any scripture on them.
Why didn't God take THOSE plates up into heaven?