Yes, but not too much ahead. They can hang out in the fridge for a couple of hours, no problem. I'd make sure to cover them well with plastic to keep them moist. Do not add any of the crackers or cheese straws, etc., until ready to serve so they don't get soft. Leave your jars on the counter for 30 minutes prior to serving just to take the chill off. If you want to make them even further ahead, I recommend assembling the picks ahead and then assembling the jars shortly before serving.