We often see unrated players in a high rated section. Do not be surprise that they won the section. Most time they come from other countries, such as India, China or Europe. They are already strong players, just with no USCF ratings.
Therefore initial rating can have big difference, depending on the TDs, sections and initial performance.
Anyway, USCF considers that your rating will be stabilized after 25 games. Before that, the rating are marked as provisional. No matter what is your initial rating, your rating will be adjusted to real level with the ELO formula based on your performance in future tournaments. If you start low, you may have many rating jumps in future. If you start high, you may even see your rating slipping down for a while. So wait until you have played 25 rated games.