I went rumaging through my Cat books and surprisingly found a Preco No. 1 Terracer parts books effective with serial number 9B1887-UP. The parts book looks like the typical Cat parts book for the older machines, brown cover printed in the Cat style.
The book referenced the tires not by part number but rather by size, and provides a picture of the tread design. Front tires 4.00x12; and rear tires 6.00x16. I'm glad that the Precos used the Caterpillar markings. I will post photos when I get it restored...Someday!