Third Link Sensing Spring 72089337.
AC Tractors 5040, 5045, 5050.
The paint is weak on the back, not bad, I didn't catch it with pictures.
Aftermarket suppliers state this will also work on,
White 2-50 p/n 31-2902007
Oliver 1265 p/n 670813A
Long p/n TX11294
This is a new old stock OEM Allis part.