if Choc was use instead of Dun then yes, seems like Mauve has more of a chocolate tone, Platinum blue look more bluish.. but that may be because of the best Platinum blues I have seen are based on Silver instead of gold
Blue(Bl/bl+) Cant dilute Pg and Ml(lacing) on a Extended black background, allowing chocolate(or Dun) to Dilute it... on the rest of the body, blue and chocolate mixed together and makes for a Mauve/Platinum blue colored bird..
pay attention to the brown/chocolate looking chick...
his dad was a ER/ER brown red Game bird.. mother is a Buff Cochin hen
and as adults
so as you can see, the chick you posted may look chocolate, but it may not look chocolate at all at a later age
looks to be a Extended Black(E/E) or Birchen(ER/ER) bird with Dark Brown(Db) this gene, dark brown will turn him into a black tail red/orange bird, Db changes the chick´s black down into a brown colored tone...