Is playing against an opponent's known "misbids" a good way to defend against a contract?
Assuming no psych bid: South has a balanced hand with 12+ to 14 HCP presumed to include Spade AKQ for his 4-card holding. That leaves very little room for additional values in his hand. With a presumed (23) or (33) holding in the minors the likely reason to have not opened one of those, planning a rebid in NT, is that they are both bare of high cards.
It's Rubber Bridge so I'm leading the Club K expecting to find partner with a good (45)  or (53) holding in the minors with at least 4 Clubs. We will strip South of his side suit exits and make him give me my two Spade tricks. I'm looking for a 2 or 3 trick set here, and at dinner Partner and I will discuss the value of voids in Opener's suit, and why we didn't get 500 or 800 on this hand.
I can only ever lead Spades from my hand safely once; and I need to save that in case I get endplayed later in the hand. So I'm not leading Spades on Trick One.