That Old Car's Spotter's Guide" for GMC/Chevy trucks definitely is NOT a be-all, end-all source for info, especially VIN's. My last SIX trucks, both GMC and Chevy, had VIN's that did not fit the format as described. These were: '67 GMC Sub, '68 C-10(x2), '67 C-10, '55 Cameo, and my son's '46 3100.

I take that book as an source of entertainment and not necessarily valid info!

Pessimist - Sees glass as half-empty. Optimist - Sees glass as half-full. Gov't- Sees glass and takes it from you because you have a glass.
Political Correctness: A philosophical belief system bereft of common sense and logic, that supports and rewards ignorance and stupidity.