Isn't copyright based on the time since the author died? Like thanks to Disney's bullshit, life + 70 years or something? Not sure if I'll still be alive in 4023, though I don't have a crystal ball.

Presumably if you know whether the author is alive or not, you'll be safe in knowing if it's under the copyright still, assuming it hasn't had a creative commons license attached or been put into the public domain.