And to answer your question no they don’t need to be changed but you will need to remove the rear ones to get the manifold of chances are most of the studs will come out with the nuts over half of mine did.
I soaked with free all for a week or so and was able to break them free relatively easy, on install I used ample anti seize so they would be easy to take out if I ever had to again. When you install it’s almost impossible to have the rear studs installed and then mount the manifold I found it...