Lionel did use a car that looks exactly like this in their Std-O line. (Because of the door type, they called it a reefer, even though it has no hatches, either for ice, or for accessing refrigeration machinery.) I do not think that Lionel decorated your car, though. Lionel had the practice of putting the first year of the car's production as the BLT date, regardless of when the prototype car was built. Lionel did not make this sort of car until 1973, but your car has a build date of 3-72. This makes me think that it was decorated by someone other than Lionel.
Possibly, it was decorated by a third party for some promotion, or as a club car. There were a few companies who would do that, and at least some of these included a mark or serial number on the car someplace, so you might look for that. It might also be that someone mounted an AHM body on a Lionel frame. I have always heard that the Lionel cars were, or were based on, the AHM cars, but whether bodies were actually interchangeable, I don't know.
Edit: Just saw Bill's post. The steps certainly are different. Making me think it's a repaint of a Lionel car, then.
