Cholly

I have done some short research about the differences between de woody ligh sixer and the heavy sixer And now I came out with a question that I hoped some one in this forum can tell me My question is: What I have learned regardibg the serial number of a heavy sixer is a series number with a letter and on the sticker said sunnyvale ca (California). However, I have come across now with another original heavy sixer with PAL. The original heavy sixer that you can find in America has the system NTSC (USA). Would that also explain the difference in terms of the serial number without a letter? The one I have now does not have a letter behind the serial number. But it is a heavy sixer with PAL! Picture1 is a heavy sixer with NTSC (USA) and has a serie nummer with a letter on the end Picture 2 is een Leisure PAL Heavy Sixer Atari 2600 Woody Sunnyvale with only a number ?