There is no date on the catalog by the letter from Dan Meyers (page 30) talks about it being the end of their ninth year. SWTPC was founded around 1963 so this catalog was printed around 1973.
Each page image is 6 by 9 inches and is saved as a 100 dot
per inch JPG file. The files are about 75k to 150k bytes in size.
Michael Holley's SWTPC Collection Home Page