Ral code didn't start until 1993 according to google which is longer ago than I thought, I just looked out of curiosity.. !
I imagine someone who had powder coat may have a ral code, but its likely plain white..
The original colour has a slight pearl to it or at least it did on mine.. When i painted mine I used Rover alpine white which is a very pure white, with no yellow etc.. becuase I had some from a Land Rover resto leftover! I like it, and because I am not a fan of the weird bronze and it would be difficult to paint for an amateur like me I used a quality rattle can of Honda amthyst, which is a colour that I love and clear coated the lot. It took a lot of thin coats and fiddly prep but its lasting well and I was happy. I will add a couple pictures in a bit.. not sure if any of this helps but you dont see many proper Kona's out in the wild now so maybe it will?! cheers Ben