Weekends are mostly for little rest and relax, even for builders and solopreuners. So a little late waking up is quite normal.
From my past experience, I have observed that a little late waking up on the weekend messes up the waking pattern, from Monday onwards. You need to struggle a bit more. I prefer to keep my waking time the same, all round the year. It gives me further privilege to wake up any day without much effort. Between I'm a morning person.
How do you prefer waking up the entire week. Does keeping a regime helps you to be productive? Are you a morning person or a night owl while working on your product?