Good Morning,
That patina is what comes with age when dealing with the oldies. As long as you do not have pitting or rust, you just have natural aging of the steel. Sounds like the musket is in good shape and Renaissance Wax is the best. However, I just do not have the patience to deal with waxing my weapons. As one who has muskets back to the Revolutionary War, I have to fight constantly against mother nature here in South Florida. My go to is BIRCHWOOD CASEY Barricade. In 15 years of usage, I have never seen rust form on my muskets.
Downside to Barricade is its longevity. Because all my muskets being shooters, they do not sit too long at idle. After the range, I clean and then spray the metal with Barricade and the wood just gets wiped down. So, if you do not plan to shoot them, then Renaissance is the way to go. Just take you time and enjoy the history in your hands. Randy