Here is a link to ponder. Reloading Tips - precisionbullets.com It's from Precision Bullets website. The problem with the roll crimp on non-crimp groove, coated/plated bullets is the fact that the crimp will cut through the coating/plating and cause leading, which is one reason to use coated/plated bullets. If there is no coating or the coated/plated bullet has a crimp groove then yes, roll crimp if you like. Hope this helps
BTW- Since there are no official rules, anyone may do as they please.