My Oliver 1650 operator's manual shows the blinking light on page 2-4.

My 1650 has the blinking light on it and it works in conjunction with the same light switch that works the headlights........  Looks original.

In fact, when I bought the tractor a few years ago, the blinking light had a plastic sticker on it that said to remove the light if the the tractor was to be used in California.

Ronnie