Yes, you're correct: a "guida turistica" can both mean "the person who guides you in a museum etc." or a "guidebook". "Guida" alone can mean "guidebook", "tourguide" or just "way of driving". For example: "la tua guida è fantastica" can mean "you drive in a wonderful way" if you say it to the person driving the car, or it can also mean "your tourguide is exeptional" if you tell that to the director of the museum you've just visited. I hope I've been clear enough and I haven't made too many mistakes!