That is not true. The color of the tail trim is a polymorphic trait in rivulatus. It has been well known for many years now, that white and gold trim even come from the same wild populations of rivulatus.It has a silver edge so it's not a Rivulatus (gold edge),
Blombergi is a rare fish in the hobby. It typically has a very narrow tail trim, unlike the fish in question. With out a known collection point, no reason to suppose the fish in question is blombergi. The scale pattern does not differ between these 2 species; only stalbergi has the very different reverse scale pattern.
The white trimmed rivulatus are very common; even a couple years back they were more common at the box stores then the gold trimmed, for at least a couple years.