1965 Solid Copper Quarter

Ok, there seem to be two possibilities:

It is just a circulated coin that was plated after it was worn (or else the plating would be worn off)

Or it was a planchet of solid copper stuck in the bin, or something ,that was stamped.

Most seem to think it was plated because the other option would be very rare. It's very unlikely but entirely possible, no ?

So ... doesn't someone know someone who would know how to tell for sure if it is or is not copper ? It can't be that hard !

If the coin was plated, I'm not sure if XRF can get beyond surface to reveal the composition?
If plated, I imagine this would affect surface details, and there might be some clear evidence on the edge that an expert's eyes could detect?

Someone on another post suggested that it be graded/slabbed. Any idea what that is and where it can be done ?

Picture color not quite accurate ... looks exactly like 30 yr old copper pipe color. It's darkened over the years.

It appears that if it's not plated it is worth quite a bit (whatever that means) so ... "if it's too good to be true .....