...Yes, and it's surprising how people don't even notice that though...
WSJ raws that come out online are 100% leaked raws. In fact, you can say every single manga that have furious race of speed have leaked raws. These leaked raws can come out as early as one entire week before the actual release date. In another word, if you think you're going to randomly pop into some bookstore at Japan expecting to get the raw that speed Manga Editors like mangastream gets, then you'll definitely be disappointed unless you indeed are extremely lucky to get into the right one...-_-"
BTW, why don't you check the content of the magazine before you actually buy it? I thought some bookstores in Japan do allow the customers to open the package to check the content though...some even have the books on the shelves unwrapped. Why buy it when you didn't even check first if you actually are getting the right one? -.-"
And if you ask where do people get these leaked raws...dunno. Since getting the fastest raw and monopolizing them is one of the thing speed groups are after, they usually don't tell you where they buy their things as well. I heard of some rumors that the leaked raws are mostly from China though, not Japan. Not completely sure if it's true or not...-_-"