When was the Yellow light MPX stereo introduced?

[L78Impala]

Jeremiah,
Sorry, I was not trying to imply that the 9 was for "79".I asked because my friend said that he found a five digit number after the radio serial #. The five digits were also larger font size. The number as listed was 1059. we were thinking that if this was a date code it would put the date at October 5th 1969. which would probably mean that this was not the correct radio for the car. But right now we are just guessing on the date code.