They aren't from LL bean are they because LL bean will take things back years later.
I think you will probably have to throw them away. I would be surprised if a Goodwill would try to sell a pair of shoes with two different sizes. I think they might also be uncomfortable for someone with the smaller size as well.
You can always put them on CL with a "make offer" statement. Maybe you'd get $20. But, I'd probably not go through the hassle and either give them to a friend (we all have the ones who LOVE a good bargain!!) or donate to GW.
I would try contacting Cabellas. Explain that you rarely wore them because they were uncomfortable and that you finally realized the problem. If it's an obvious defect they may offer you a small store credit or something.
Re: WWYD (NBR)
I think you will probably have to throw them away. I would be surprised if a Goodwill would try to sell a pair of shoes with two different sizes. I think they might also be uncomfortable for someone with the smaller size as well.