Here's another Sweden overdate, the 2 Ore 1906/5. This one is described as "rare" in auction guides from Sweden. First, the markers compared to an overlay of the 5 used the previous year: Here's the premium for the overdate in Krause--it's true to prices asked for in Sweden. I have found two of these--maybe you'll find one? This example is in a nicer grade--it easy to see the overdate:
You may easily have some overdates in your collection. There's a lot of countries to choose from that produced them into the 20th C.