Um, no. A small minority of Ahkenazic Jewry were talmidei HaGra.
Furthermore, many minhagei HaGra are hearsay, the Gra never compiled a list of his customs. Curiously, there is no such thing as “Siddur HaGra” because the Gra never compiled a siddur, and no one knows (or even claims to know) from which siddur the Gra himself davened.