Don't think so. They look like old school Chief frame equipment diagrams or similar. Top numbers are mm bottom are inches.
The first diagram. The length measurements are notating where key frame components or measurement points are located in reference to the front crossmember or front wheel centerline(???). This diagram is showing one frame with a 131.5 wheel base and that's it. The frame is shown with 2 section heights as well. There is usually a page that shows what all the diagrams encompass and only thing I can think is this is for all 131.5 frames 1500 and 2500 hd's etc. All the dimension listed(body mounts, wheelbase etc.) would be the same for both frames.
The second diagram shows all the width measurements from the vehicle centerline. It's showing a 21.34 measurement(center of the vehicle to center line of the frame just forward of the front bed mount to 17.05 at the tail end of the frame. 3.29 more narrow per side.
Imho both diagrams are working off of the rear side of the front crossmember. Chief, Blackhawk, Gm, all put out frame diagrams like this and this diagram is not what
@MrPink thinks it is and why he believes the #'s are incorrect.
Thank God technology has improved and us collision guys aren't working off sheets like this any more. Taking frame measurements off a moving part such as a front spindle or front wheel centerline is not the way to do things.