The printer's marks are in red ink. There are various page numbers. They appear to be random pages.
Blue ink is used for corrections and deletions.
The printer's marks are done in red pencil. Corrections and deletions, of which there are many, are done with pencil and red ink. Pages are made by typing on a separate sheet of paper and stapling to the page where it is to be inserted. Six sheets 14 x 21.5cm. Inc. Other five sheets are yellow carbon paper.