If the question is about commercial paper there is still no definitive answer. The repetitive logo at an angle on the back is most likely 1990's. However, they also made paper for smaller prints that had a single logo with the date printed. These papers were mainly for commercial labs that printed for the consumers or other customers. Newspapers and other organizations used Kodak paper, but it did not have those logos. I was still buying Kodak paper in the 1990's, most RC polycontrast, by the box of 100 sheets for my own darkroom printing. That paper had no logos, yet it was Kodak paper.
Here is some information from the film and darkroom forum based in the U.K.
Excerpted From:
https://www.researchgate.net/publica...ographic_paper
Notes on dating photographic paper
January 2005
Project: Silver gelatin characterization
Authors:
Paul Messier
Yale University
2.3 Back Printing
In some cases manufacturers applied inked logos and other information on the
reverse of their papers. Though there are some exceptions, back printing is consistently
used only on Agfa papers and on the longstanding Velox brand produced by Eastman
Kodak.
While some superficial differences are evident in the typefaces, size and
positioning of the Kodak back printing it is uncertain how much value these observation
have when it comes to dating photographs. This author is just starting a methodical
chronology of Velox and other back printing on Kodak papers and any useful results
from this exercise might be a year or two away. A preliminary finding is that the single
word “Velox” with no other graphic embellishments was used to mark papers
manufactured in the United States dating from the late 1920’s to the late 1940’s. After
Topics in Photographic Preservation, Volume Eleven (2005)
125
1950 or so, back printing on Velox stacked the words “Kodak / Velox / Paper.” The
three stacked words were used at least until the mid 1960’s. Another finding is that
Kodak papers manufactured in England, and probably elsewhere, had completely
different typefaces and back printing styles.
The Agfa company was much more consistent in its use of back printing. While
not every paper in the Agfa line carries back printing many do. When present, Agfa’s
markings can sometimes be used to establish a rough date of production. (Agfa-Gevaert,
1997; Auer, 1999). Prior to the late 1950’s, Agfa identified its papers using two words
comprising the manufacturer name and the brand name such as “Agfa Brovira,” “Agfa
Portriga,” “Agfa Lupex” etc. Following the late 1950’s use of the brand name was
dropped, leaving the one word “Agfa.” Aside from dropping the brand name in the late
1950’s, Agfa changed typefaces, added and subtracted quality control markers and other
graphic elements over time. A chronological compilation of this information would be a
tremendously useful, though the author knows of no such resource.
On the whole, the use of back printing for dating papers is of limited use since
comparatively few papers show any manufacturer applied markings. Though relatively
rare given the entire population of photographic papers it is a remarkable fact that many
of the questioned photographs attributed to Man Ray and Lewis Hine, purportedly made
in the first part of the 20th century, were found to contain the one word “Agfa” marking
on the reverse clearly indicating the papers were manufactured after the late 1950’s.
[End Excerpt]
The full text is available at the link at the start of this post.
Oh, and on a side note, Kodak stopped producing black and white paper in 2005.