Open a seed (any seed, doesn't have to be your own) in valheim-map.world and there's a list of checkboxes down the right side. Checking the box labeled "Misc" shows the location of things like "StoneCircle" in the Meadows, and "Runestone_Mistlands" in the Mistlands.

So at a guess, the answer is "yes, you've just missed them"... although there's no guarantee that "Runestone_Mistlands" is actually lore-related, or for that matter, even a runestone at all.