The so-called 28 Fundamental Beliefs were never intended to become a creed. Sadly, they are often used as a creed today. Those beliefs are stated in short paragraphs, general only one, on a page just before the chapter which explains the belief. The short statement is the official SDA statement. The expanded chapter which follows, is not
In the original book, Chapter 17 deals with Spiritual Gifts. The Statement at the beginning mentions EGW and is therefore the official statement of SDA belief.
It is on the basis of #8, in the set above of 13, which has been the standard for many years, and is still the one most often used, that I say that the official position of the SDA Church does not require a member to believe that EGW was a Biblical Prophet.