The original GM Master Parts List has had many revisions over time. Parts are superseded. Illustration drawings are updated. Such is life.
Sometimes I find the best information is usually in the older versions that includes the year of my truck.
Rather than purchase a lot of versions, I just use
http://www.gmpartswiki.com.This is helpful to track a part's history.
For example:
* go or click to the link
* click on search
* just for practice enter 5592626 (this is the early AC fuel pump 9803)
* the search comes back with a listing of 5592626 found in different versions of catalog for many years.
* when you find a year or catalog you like, click on the small page picture for more detail
