The first USAF aircraft " DESIGNED" to utilize an all rocket armament was the Convair F-102 Delta Dagger. Even though the F-86D Sabre used an all rocket armament the aircraft came off the drawing boards with a configuration to use a 20mm cannon or an all rocket armament of 24 / 2.75 Mighty Mouse Folding Fin Aircraft Rockets, FFAR,s. After testing and evaluation the all rocket armament was selected and all plans for the use of the 20mm cannon on the F-86D were dropped in Feb 1950. The Delta Dagger never had any provisions for a gun to be used in its design. It was strictly designed for all rocket armament.
This is really splitting hairs, but the F-86D used unguided 2.75 inch rockets while the F-102 used Aim-4 Falcon guided missiles.
Darwin, O.F. [alien]