إرشادي an adjective derived from إرشاد = Guidance دليل is a name, if he is a person it will mean guider , this is in its origion in the old arabic books, but recently it is mostly used with books to refer to guidebooks. thats why you describe the book as being ارشادي and you say كتاب ارشادي but when you say دليل الهاتف you do not need to use كتاب for the word دليل by itself refer to guidebook. ==== there is also another meaning for دليل => evidence or poof. the context will show which meaning is intended by the speaker.

There's no difference. example Tour guide = دليل سياحي = مرشد سياحي