I saw it in a Reddit comment a few years ago and I don't know if it was written originally by the commenter or if it came from somewhere. Basically, humans in the distant future after some apocalypse-level event see the Voyager with the original NASA Golden Record crash into Earth, and think it's from aliens. The gist of the story is them figuring out how to decipher what the symbols on it mean, and the story ends with them realizing that the aliens who sent this device were actual humans from super long ago.
I think it's this short story written on Reddit, by the Reddit user named wawin.
The main character rushes to examine a crashed alien spaceship, and they find a golden record:
My colleagues open it completely and remove what appears to be a Golden Disc, and a strange small casing containing a needle
After they figure out how to play the record, they discover it's from Earth:
The diagrams and pictures started to describe in detail what the human body was and how we reproduced. After all this excitement, turns out we had opened up a message sent by ourselves.
The message includes a reference to Jimmy Carter, the President of the United States. The story ends like this:
As we fell into silence, my youngest girl asks me: "Daddy, who is Jimmy Carter, what is a President? what is the United States?".
I look at her eyes and simply say "Honey, I don't know..."
Could you be looking for "Voyager Found"?
NASA’s Voyager spacecraft has just landed: meet the aliens who found it.
Found with a search for site:reddit.com fiction "golden record"
It does not have a revelation that the people involved are distant humans, though, but rather on them deciding to communicate with their neighbors as a result.