There is currently much speculation as to the quality of the pods produced from culinary seeds. Two varieties of Opium poppy, the 'Przemko', and the Tazmanian 'Norman' strain are both bred for "extremely low morphine content" -- Somewhere along the lines of 0.01% in the mature seed pod.
These varieties were developed specifically for the purpose of creating a variety of Opium Poppy that is only useful for seed. Since these varieties were bred specifically for use in culinary applications, it would seem logical that the major spice suppliers would migrate to using this type of seed. Provided of course that the specialized breeding produces no change in the quality or flavour of the seed.
Colloquial evidence suggests that McCormick for example may be slowly migrating towards using these specialized breeds that have a very low alkaloid content.
Some people have reported good results with McCormicks, while others have spent a great deal of time growing only to be dissapointed. A variety of factors could be contributing to the mixed results -- everything from individual tolerance on the part of those who reported failure, to the potential of a placebo-effect on those who have had success. Or it could just be that McCormick aquires its seeds from several sources, only some of which are providing the new low-alkaloid varieties.
Although some suppliers may already be using these seeds, their penetration is by no means complete.
So if you are just looking for seed to grow poppies purely for their aesthetic value, you're in luck because they will sill grow. But if your intentions are to use the plants for their alkaloid content, then at this point it looks as if its just the luck of the draw.