I hope I'm telling you right, if not others will quickly correct me I'm sure.
The build sheet is the sheet that is used as the car goes down the assembly line, it gives detailed build data codes used by the assembly worker(s) for every component, assembly or system that is placed in the car during the assembly process.
The window sticker on the other hand lists the Engine, Transmission, Color / Trim information, Standard Equipment for the Base Model and Trim Level and major selected options or packages that were installed in the car at the time of manufacture, along with any dealer installed options or accessories, and the associated MSRP for the base vehicle and each option or option package that was installed.
The window sticker will not get into the detailed listing of parts codes used to make up a major option component or package. Example RPO Z06: The LS6 engine code, FE4 suspension code, shock codes, etc. will generally not be on the window sticker, but will be on the build sheet because the assembly line workers use those codes to select the correct part(s) for each car as it is assembled.
Did I make sense of all that to you?
vettepilot