Yes, they set about on an academic exercise and found themselves with a surprise bestseller. They spent the rest of their days churning out subsequent editions. It was kind of the Harry Potter of its day.

They revised the stories themselves. The initially publication was an anthropolical work collecting folk tales but it became succesfull as childrens litterature. So in subsequent editions they revised the stories to be more child friendly (according to the standards at the tme).

This does not mean the original publication was completely uncensored though. In any case orally transmittet stories does not have a single canonical version.

After the second revision only Wilhelm, Jacob did add some "scientific remarks" for these. The biggest problem had been the idea of the Grimms' of the books being both a "scientific" collection of stories (which never were meant exclusively for children) and a book for children.