Sounds like you answered your own q. If selling one, the .338 is the one. Personally...that is what I would do, I have no use for a gun like that - sounds like you don't either.

Regarding the lefty thing...Assuming they are left eye dominant also - (check that first) they would probably end up being a much better shot when they shoot the way of their dominant eye, and dominant hand. But changing is certainly not necessary. Really up to you. Since they are actual Lefty's..it may be eaiser for them to handle also.

My daughter is right handed...shoots right handed, but is left eye dominant. She's a good shot, could she be better if she switched? Probably, but she doesn't care enough about it for me to buy her a LH gun and get her to re-train herself left handed. The key for shooting gun with your off dominant eye, you have to close the dominant eye when aiming/shooting.