No. Techron is a Chevron trademark. Costco does not license or advertise Techron in Kirkland Signature gasoline. If a bottle or a pump says Techron, it is a Chevron (or Texaco in some areas) product, not Costco’s warehouse fuel.
Costco still uses detergent additives. U.S. Costco gasoline is TOP TIER, which is a performance spec for deposit control — not a chemical brand name. Details are in does Costco gas have additives? and the Chevron comparison in Costco or Chevron.
Can you add Techron yourself?
Aftermarket Techron bottles are sold for use in any gasoline, including a tank you filled at Costco. That is optional, not required for TOP TIER fuel, and it does not turn Costco gas into Chevron gas. Follow the bottle dose and your owner’s manual.