No good counter-argument has been published by LDS scholars.
The plates were shown only to people Joseph Smith chose. Family.
Money backers. Early believers.
Then they were returned to the angel. No scholar or neutral party ever saw them, and none ever can.
It is not proof of anything on its own. Plenty of genuine ancient objects are lost.
But it does mean the central physical evidence for the book is permanently unavailable for testing.
An interesting one. Witnesses put the plates at 40 to 60 pounds.
Solid gold that size would weigh about 200. But tumbaga is different — a copper-gold mix used in Central America, gilded on the surface.
Plates that size in tumbaga would weigh about 53 to 58 pounds, and look like gold. That fits a real object better than a forger would have guessed.
Strong for you on the main point, but give them the tumbaga argument first. It is a good one, and pretending otherwise costs you.
"Is there anything that could be examined today, either way?"



Tumbaga is a copper-gold mix, and plates of that size would weigh what they said.
Apologists argue that the reported weight fits a real ancient object. Tumbaga is a copper-gold alloy, gilded at the surface, and it was used in Mesoamerica. Plates of the size described, made of tumbaga, would weigh roughly 53 to 58 pounds. They would look like gold. A forger guessing at 'gold plates' would be unlikely to land there.
The return to the angel is explained from scripture. The record was not meant to convince by proof. Ether 5 says witnesses were appointed instead. And Richard Lloyd Anderson's work shows those witnesses held to it for life.
Strong for you, but hand them the tumbaga point first, because it is a good one.
The core fact is conceded on all sides. No independent examination ever happened, and none is possible now.
The tumbaga answer makes the reported weight of 40 to 60 pounds add up, where solid gold that size would run well past 100. It still cannot stand in for the missing object.
What is left in dispute is only how much the insider witnesses can carry instead.