I don't think that Germany would have much to gain if they had chosen to invade us. If Germany had invaded us, it would have caused some serious issues in politics and security. There's also quite a few Swedes or Swedish-Finns living in Finland (today about 290 000 I think), it's doubtful that a hostile occupation of Sweden, would have led them to looked at it on the bright side. It would have also drawn much needed troops from the eastern front and jeopardizing supply their lines even more. Further, it isn't a given that even with a "small and antiquated" military, that Sweden would not have given Germany, or any allied country foolish enough to invade, a real pounding, much like the Finns gave the Russians in the Winter War.
Not forgetting that hunting is a second nature to many Swedes especially when it comes to the älgjakten, which has a roughly 100 year old history with thousands taking part. They wouldn't have a clue about how many they would meet with more than just the one hunting rifle with telescope, able to track and camouflage....
Maybe I'm just a tad over patriotic here, but who knows.