If all the ski goggles in the box are completely identical, then they should only have one SKU. However if some are pink and some are red, then you should use a different SKU for each color or variation. That way you know which color sells best.
You can make up your SKU however you like or let Amazon assign one, but if Amazon assigns it, it will mean nothing to you. If you make up your SKU you can add in different info to the number to indicate cost, when listed, where stored, initial price, maybe even ranking at Amazon and how many other sellers are on the listing. I even have part of the code indicate if I made the actual product page. In other words, set up your SKUs so they help you with important information and with restocking.