Entirely depends what kind of shop it is. They should be though just because it's better to not over order new stuff that people won't buy or under order stuff that's high in demand. It's very important stuff for stores and publishers to know (especially if there is a particular series that you want around and is in danger of being cancelled).
Usually you have to buy a copy of "Previews" and get them your order form before they send away their orders. That's how its usually run, but sometimes they'll just have you fill out a store only form and they pull your stuff every week, but you also have to do that every month.