While 1991 does seem too recent for the text, 1961 is not possible given it makes several references to later years, up to 1965/1968.

I am curious if this article has been scanned by a machine that attempts to use OCR to improve quality - at the expense of occasional mistakes. "dress" in place of "chess" looks close in font appearance, but far to mistype on a keyboard.

Are you referring to "(so goes an old joke in modern dress)"? I'm pretty certain that is intentional. It's an old joke that has dressed up modern.