It depends on the facilities of your local school system. When you enroll your child in school, you should always make sure you agree to their curriculum before completing the enrollement. Make sure you arrange when it will be best for you to visit. Most schools where I live will not let you enter the school grounds/building during school hours unless you get a permission slip in the office. Even so, there are times in which they can not let you enter, depending on the activities the school is having. You can ask your child's teacher permission to see your child during recess, through the school gate.
Remember that this will vary from school to school. So make sure you ask all of those questions when enrolling your child. You should always be able to call the school at any time, but the information you will get from the office personnel might not be too accurate.