I don't know if this would be the right category. I recently noticed that one of my graded eagles was placed in slab crooked. Silly question but is now worth more or less? It's a 1993 MS 69
The coin being rotated inside its slab won't devalue it in anyway - it's still the same coin, with the same assigned grade. Sure it may be kind of annoying to some folks with extreme cases of O.C.D., but anyone who's seriously interested in purchasing something like that shouldn't be turned off by such a minor issue. It's not uncommon for coins to rotated a bit before being sonically-sealed. -Brian