Just mirroring previous comments, I have also heard from some breeders and more experienced keepers than myself that some of their snakes aren't even offered hides any longer because they do not use them. Because of all the comments about this so far, it might not be such an uncommon occurance.

If feedings and sheds are all going well then I wouldn't worry about the lack of using a hide spot. He may just be comfortable in his enclosure, or prefer some of the tank decoration over an actual hide. If anything about his feedings appears to be out of the norm for him though then I'd definately start digging a little further.