I would say that type of error would be highly improbable. It require the mint mistakenly switch half of a die set. Like oops I put in the 1959 obverse but forget to take out the 1958 reverse.
If you find one, it is probably fake. As far as I can tell, no examples of a 1959 wheat have been verified as real.
One place put the estimated value of the one known coin in existence at $25,000 with the caveat that they could not guarentee that it was real and the teaser that it would likely be worth $100,000 if ever proven to be real by matching it to a die.
In other words if you could find a 1958 penny that was struck with the same reverse die as the 1959, you just proved that it was struck with a real die at the mint.
Those are interesting stories for sure. I've heard so much about those possible types of coins existing but I wonder if those stories are like all the other odd ball ones in coin collecting.
They are a WHOPPING lot rarer than Wild Indians. Rational Thinkers might just insist they don't exist. If you happen to come across one you you could finance your coin hobby (fanaticism?) for several years.