We are refinancing a construction loan to permanent financing. If the customer has not started living in the house I'm guessing rescission would not apply. But if they have been living there for a couple of weeks would rescission apply as this would be their primary residence?

Even if they have started living in the house, it is not subject to the RofR. Read the definition of Residential Mortgage Transaction [and it's commentary in Reg Z. The Commentary page is the most marked up in my books.