The collection I purchased listed these as Scott 61 (left) Scarlet and 61a carmine (right). Scarlet is supposed to have a tinge of orange so if the right stamp is not faded then I would say the carmine is on left but not 100%.
I would tend to agree with you, albeit the stamp on right is a little dirty. Carmine is the odd man out, Your right would appear to be similar to my common scarlet. Dealing with colours is dancing with the devil.