Has the Golden Path been discovered by the Bene Gesserit before??

If the BG had known of the Kwisatz Haderach in Dune and it was supposed to be their version of the pseudo-Lisan al-Gaib, a person who knew all possible futures, wouldn't they have any kind of way to know who is the kwisatz haderach long before the child can undergo the Gom Jabbar or any other kind of test or feat? Seeing this wouldn't they have set the golden path and not the House of Atreides?