Anodizing is the artificicial creation of aluminum oxide on/at the sturface of the part. Hence, you are at the mercy of the surface condition of the part when it comes to cosmetics.
A peened surface should remain about the same and perhaps get a bit rougher depeding on whether or not your anodizing "bites" into the surface or not. Again, since you are chemially changing the surface via a process that changes the surface metallurgy, you are stuck with working with what you have to work with.
You'll probably find that some test pieces, run with varous types of prep, will answer more questions than you'll even propose.