Upidstay's comment should serve as a good reminder to pay close attention to what's in the products you buy, especially when it comes to organics. Sadly, it seems that especially with organics, there are so many snake-oils and deceptively marketed products that it makes finding good products that much more difficult.
I'm not a big believer in corn gluten as a preemergent, but I know that plenty of other people are. That being said, if you're going to sell it as a preemergent application, make sure that it's labeled as such. Also, kinda makes you wonder about the rest of Bradfield's line if they're so willing to deceive with their corn gluten product, doesn't it??