Thanks for sharing! Unfortunately, I don't think we have a definitive answer to the original poster's question. If we take the MCA rules literally along with the other information circulating, then non a/c 6's are supposed to have a heat shield. It seems we are having trouble finding evidence to support this. I find it hard to believe with the quantity of 6's produced, we haven't found a bunch of original examples with a heat shield, or even 1. I'm beginning to get the feeling the 6's never had heat shields.