Now that the doors of pedantry have been opened, the sources used in the article don't actually specify that it was a Finnish "road sign" first, only that it was first suggested as an official symbol by the Finnish national local history association in the 1950s (having been used in all of the nordics in an unofficial capacity a lot longer), and that it started being used in all of the nordics in this official capacity in the 60s. The sources that say where Susan Kare got the inspiration more specifically than "from the nordic/Scandinavian countries" all seem to state a Swedish road sign, though exactly where she/apple got the inspiration (if they even remember correctly) is probably unimportant.
