TOPIC: 1972 Lo-Pro Sidewinder questions

Im in the process of restoring my dad's 1972 Sidewinder and yall have already been a big help in assisting me in figuring out the model of the boat. I have just a few questions. First, do yall know anywhere you can look up the HIN number breakdown for these boats? I have the number because my dad had it written down but I would like to figure out what information the HIN provides. Second has anyone restored one of these or added speakers to one? I would like to have some way to play music on the water but also want to keep the original look of the boat at the same time. I've had a few ideas but seeing what other ideas yall would have. Lastly, has anyone added cupholders to one of these style boats? I also have an idea for this as well but just want to see what others have done or other ideas.