I do sand it...rough it up so the CA sticks. I don't fully sand off all the paint though...I like the colors to show a littleLooks great! You may want to consider sanding your aluminum, especially the side that has the paint or inking. That can helps achieve a better bond with your adhesive.
hahaha. OK. (And you're right...it is purple heart...verbal typo).That is purpleheart and not rosewood to begin with. I believe it is not a good idea to leave the paint or paper on aluminum. if you want color then add a thin piece of acrylic colored or use colored woods on the ends like spectraply. Third always and I mean always turn in from the ends to the center and not to the ends. This is for any blank. This is a huge reason you see so many blowouts on the ends of pens here. Otherwise you have a good start and learning from mistakes will only make your work even better. Good luck.