Welcome to the world of cast iron keels. We 34 owners are very familiar with that look!
As for the one side only thing- I was told somewhere along the line that iron keels are normally cast with the starboard side up and because scrap iron is used, a lot of slag and impurities float to the surface, leaving that side much more prone to rust and roughness. Certainly is true of mine. I found that this year even with only 3 months in the water ( fresh) I had 2 or 3 little spots after my big project of taking it down to the metal, coating with rust converter and 4 coats of Interprotect 2000