If you just bought it now and don't plan on hunting until this fall, there's no need to wash it right away. Put it in an airtight container until hunting season, then you can either wash and dry it before going hunting, or simply regenerate it in the dryer and be on your way.
After sitting in the store for who knows how long I would want to wash it and get all the foreign odors that it came in contact with it over it's shelf life off ASAP, I would not want it stinking of foregin odors and then to store it in an air tight container with those foregin odors having no where to go but be adsorbed by the carbon..... Who knows how many times it was handled and tried on with some guy stinking of Brute and Old Spice....
This is why I would wash it firstand then store it until hunting season.