According to Kona's website, the headtube angle should be 62 degrees with 80mm forks.
I have just swapped out my forks for 2010 Fox Float 36's, they are currently at 100mm and the headtube angle is 65 degrees.
Will lowering them to 80mm make the headtube angle right or should I just leave them?
I would leave them ... with sag factored in, I suspect that your head tube angle probably hasn't changed that much. If you don't like how it rides, your want less travel, then consider changing the forks travel.