Set your smoker to a temperature range of 225°F to 235°F.
In a medium bowl, mix 1/3 cup olive oil with thyme, rosemary, parsley, and garlic. Reserve one-third of this mixture for later use.
Trim excess fat from the kobe prime rib, leaving some to enhance the meat's flavor. Coat the roast with the remaining 3 tablespoons of olive oil.
Generously season all sides with sea salt and black pepper, pressing it into the meat with your hands.
Cover the roast completely with two-thirds of the garlic and herb mixture.
Place the roast on the top rack of your smoker. Insert a digital thermometer into the center of the meat. Position an aluminum pan underneath to catch drippings.
Smoke the roast at 225°F to 235°F until it reaches an internal temperature of 100°F, which should take about 2 ½ to 3 hours.
Increase the smoker temperature to 500°F and continue cooking until the roast's internal temperature reaches 118°F to 120°F. Remove the roast and apply the remaining one-third of the garlic and herb mixture.
Let the roast rest for about 20 minutes. Slice and serve with au jus and creamy horseradish sauce.