This drawing appears in a Boeing Manufacturing Training publication titled "707 Reference Guide" first published in May 1958 and reprinted in October 1960. It is evidently intended for the guidance of assembly line workers. The drawing shows three 707 variants (reading up from the bottom of the page):

Model Body Length Remarks
Original Basic 707 128 feet 10 inches No customers shown.
Basic 707-120 (& 220) Long Body 138 feet 10 inches The Original Basic 707 has been lengthened by 10 feet with the insertion of two 20 inch sections aft of the wing and four 20 inch sections forward of the wing. Customers listed are: Pan American, American Airlines, TWA, Continental, BAC, Braniff & Cubana.
707-120 (& 220) Short Body 128 feet 10 inches The Qantas 707-138. Same body length as the Original Basic 707 but with the deletion of one 20 inch section aft of the wing and the insertion of one 20 inch section forward of the wing.