First AC-130W retired

The first AC-130W gunship to record a combat kill has been flown to its final home at Sheppard AFB, Texas whereby it will become a ground instructional trainer for ammo and armament students in the 363rd Training Squadron as well as crew chief student in the 362nd Training Squadron. The aircraft was received from the Lockheed-Martin factory Jun. 6, 1989, with the original nickname of ‘City of Hurricane.’ It recorded its first combat kill on February 9, 2011 and on December 2016, it became the first AC-130W to score a combat kill with the 105mm cannon.

It's the third AC-130W to retire

What are the other two tails?

It's the third AC-130W to retire

It is the first with a combat kill with a 105mm gun.

It's the third AC-130W to retire

It is the first with a combat kill with a 105mm gun.

Your post title is misleading.

It is the third to retire.