I've just done some further reading on this and it appears "aloxal coating" is another name for anodizing so this duplicolour paint is the same as the other aluminium paint coatings (like the CRL one I posted above) and all of them appear to be a paint coating that is aluminium anodized color and not some acidic or other process that mimics a genuine anodizing process. That's not to say they would not look OK (I've not seen them in action) - it's just that they are colored paints, not clear coats.
And here's a vid on how to sand aluminium to get a brushed effect and it the importance of sanding straight.