Hi Stu,
If the plant is Meconopsis horridula it will have yellow or golden stamen when it flowers, and not cream or grey stamen. The true species seems to be difficult to raise from seed and extremely rare in cultivation, although Chris Chadwell probably collected seed in the past.
As you obtained the seed as Meconopsis horridula it probably will be a hybrid or a different species, but still a nice plant and well worth growing. There are some pale blue and white variants which need to be established as pure strains.
If you are thinking of collecting seed and passing it on, then I would suggest that you label it as Meconopsis horridula (of hort).