65 Valiant fender tag question about radio options?

My experience has shown if there is no "1" under the "Q" then the car was ordered without a radio. Your car may have had a dealer installed radio or perhaps the owner added an aftermarket radio.
But....the absence of the "1", in rare cases, could have been a accidental failure of the factory to stamp the code on the fender tag. The fender tag was not the build record/sheet for the car...it was the other way around.
The IBM build card or build sheet is the only to know for sure.
FYI...I had a 67 Charger without a radio code on the fender tag and sure enough a later owner had added an aftermarket radio.