I guess the other number marked around those cars is probably the manufacturing number, i.e., the number the car makes in the manufacturing assembly line sequence (mine too has got a number, different from the chassis number, marked all around in different parts)
The chassis number has nothing to do with the manufacturing sequence, as they can give a certain car a chassis # on the 20xx sequence if requested (as Mike has stated)
They can jump back from the 21xx/22xx chassis numbers of the regular manufacturing line, to a 20xx chassis number during the manufacturing sequence, but the number marked on the car parts just shows the number that particular car makes in the manufacturing sequence.