Those do look a lot like the Rizoma Sportline grips (I've got them too), but if you read the description, you see this:
"These Kraton Gel grips have an alloy 6061 collar that are interchangeable, require no adhesive, fits all 7/8" bars and are an open end design. These grips are made of a top ply of pvc design to stabilize the surface of the grip, under this layer is a layer of KARTON GEL designed to absorb vibration and impact."
It sounds like the only part that's actually aluminum is the collar. The colored part of the grip sounds like it's plastic, unlike the Rizomas, which are completely aluminum. For the price of these ($45 plus $13 shipping), I'd rather have the Rizomas for $60 plus shipping and know what I'm getting.