Congratulations on purchasing your 343. I have had mine for two years now; I really enjoy the boat.
I am somewhat puzzled by your question. The reading lights and cabin lights are on the same circuit breaker on the AC panel; however, they operate independently from one another. Each reading light has a black rocker switch on the chrome base. The overhead cabin lights in the salon have white plastic rocker switches that are mounted on the overhead liner about where it intersects with the starboard side of the interior, just forward of the AC panel. There is another plastic rocker switch overhead in the galley about where it intersects with the aft bulkhead that leads to the aft berth. In the forward berth, aft berth, and head; the overhead cabin light has a small black slider switch that is part of the light housing. Hope this helps, if not, let me know and I will get some photos when I am on the boat. Keep in touch if you have any other questions.