This has probably already been pointed out, but I haven't read the entire ten year history of this thread.
Harry may not be an entirely reliable narrator, and personal memories are notoriously prone to unconscious editing. Why not just figure that Harry's age and childhood media references (Knight Rider, etc.) are based on Jim's? I expect that Bob might have exact dates, but he could have ended up in a situation such that Harry no longer has access to him for reference by the time Harry is meant to be writing his case memoirs. Bob has basically moved on to a new owner by now, but maybe he gets captured by fae, or his skull home gets broken, etc.