Proof Jefferson With Rotated Reverse?

Odd type of problem. The reason is rotated reverses are difficult to spot, ignored by many, used to lower prices by others. And for errors, even the Red Book, 2011 edition on pages 404 and up give all kinds of possible errors and don't even mention rotated reverses.
On coins in your change there could be many but really difficult to spot since you would have to be able to turn over the coin so carefully so to spot that problem. And some that are 180 degrees could go unnoticed completely since many people just don't know a coin is right side up when turned over from top to bottom.
At coin shows I've used that problem with coins to lower prices. Some dealers will and others would say that is an extra bonus.
If you put Mercury dimes in an Album, all face up on the obverse, turn the page you would probably see about 20% or more all tilted all over the place. Don't know why but certain coins are just famous for that problem.
Odd that I've never heard people mention this with Jefferson nickels. Now I've got to go look at my Jefferson nickel Albums.