Research Project on CB175 manifolds: active contributions needed

If you have a CB175, could you take a look at the manifolds between the carb and engine and look for a faintly stamped number on the top edge above the bolts? You will need a flashlight, but the numbers are visible without removing anything from the bike. Once you find that number could you post it here along with the year of your bike, and if you believe them to be original to the machine? Examples of numbers you might see are 306A, 306B, 644A, 7A...check both sides to make sure the numbers are the same or different. My purpose here is to see what manifold numbers came on each of the different years of the CB175.
Thank you for your contribution to the scientific accumulation of data!