What is the full VIN? The GTS has metal badging on the hood, driver's side, front? Swinger says Dodge. Both hoods have the raised bumps that say 340 four barrel chrome inserts. Trunk lid back side has aluminum GTS trim. The Swinger says Dodge.
Google some pictures. Do not remember ever seeing in '69 a Swinger with anything other than a 340. Later years yes, but not '69. Again, this car may or may not have torque boxes with an automatic. The '69 Swinger was kinda like the first Road Runners, no frills , basic muscle car. GTX, fancy, Road Runner, cheap. GTS fancy, Swinger, cheap.