Hi Nick, and welcome to the forums.
The short answer:
Sit 'n Sail wings are not Hobie Class legal for racing.
With very few exceptions, boats are raced as they come from the factory, the theory being that with the boats being equal, it's the skill of the sailors that determines the outcome of a race, not the equipment.
The practical answer:
I doubt if anyone would seriously object to you racing with your wings, especially if you're not trapezing from them. They add weight, windage, and unless you trap from them, you're not getting the righting leverage you get from two people trapezing off the sidebar. All of those = slower.
But don't just show up at a regatta with your wings - do some advance work by contacting the organizer and the other competitors so there's no stress at the event. Most events are so happy to have new people, they'll make an exception.