In 1967, Ertl was acquired by the Victor Comptometer Corporation (maker of calculators and adding machines), and this model is from that era of 1967 to 1977 before they were sold again to Kiddie. The box says subsidiary of Victor Comptometer Corporation. Stock no. 500.
For it's vintage age, this is in great shape. Completely all metal. Wheels have some paint chips, probably from setting it down after taking it from the box. Box has some wear and an original price tag of $3.88 at Farm & Fleet. There are many of these D models out there, but not many from this era in this box! Check out my other tractor listings! I will combine shipping!