I'm pretty sure this is the manufacturer of the camshaft blank. It would then be sold to the manufacturer who would then grind it to their specs into a finished product.
1085 W Sherman Blvd., Muskegon, MI 49441-3588, United States
(231)733-1331, (231)739-2649 fax, http://www.textron.com
Primary SIC: Motor Vehicle Parts And Accessories, Primary NAICS: All Other Motor Vehicle Parts Manufacturing
Description: Manufacturing: Gray iron and ductile iron castings, camshafts for automobile and engine manufacturers.
If there are no other markings on it, then it's a pretty good bet that it's a stock cam for that motor, ground by GM.