1. Line a baking sheet with parchment paper. In a large bowl, use your hands to knead butter, peanut butter, pumpkin puree, sugar, flour, salt, and pumpkin-pie spice into a smooth, firm dough. Roll the dough into tablespoon-size balls. Place on the prepared sheet and refrigerate until firm, about 1 hour.
2. Melt chocolate chips and vegetable shortening in a double boiler and whisk until smooth. Use a toothpick or skewer to dip each candy ball into the melted chocolate mixture, leaving the top uncovered if desired, and return it to the pan. Remove toothpick.
3. Chill candies in the refrigerator until the chocolate sets, about 20 minutes. Keep refrigerated until ready to pack and keep cool while traveling.