I have the exact same Swift reefer car which I purchased directly from DOWNS. In the 1970's- 1980's DOWNS offered many cars with ACE underframes and trucks attached to repainted Gilbert boxcar or Reefer shells. I also have a Boston & Maine Reefer from DOWNS. You could get a Gilbert operating coupler or an ACE dummy coupler attached to the bolted on ACE adapter or you could get a kadee coupler attached to the underframe with scale wheels on the trucks.
DOWNS also offered a line of cars labeled "Rusti/Downs" including painted and decaled REX lowside gondolas and REX flatcars, repainted and decaled PRS 50 foot Boxcars and a line of tank cars of various sizes.
Unless you bought these cars at a train show, you chose from a list of road names in an ad in S Gaugian or NASG Dispatch without knowing what the car would actually look like when you received them.
Back in the dark days after Gilbert closed down, and before American Models and the relaunch of American Flyer by Lionel, Downs was one of the few places where one could buy "new" rolling stock. Otherwise there were just a few firms making "craftsman kits".
LittleTommy