i used to have those lights. yes that is the reverse part. the big red circle is the brake/parkin light and the clear circle is the break light. mine also had little circles on the outside for turn signals. but i agree, why would you want altezzas? get red/clears! thats actually quite unique for a 5th gen, considering you'd have to make them yourself. which i think would be funner. i would feel better knowing i custom made my own tail lights...
here's a pic of my car with them, WHICH ARE NO LONGER ON MY CAR! luckily, i sold them for the same price i bought them ;D