Jerry,
To the best of my memory, they weren't in the 1948 rules. The 1948 rules I believe were the first set of rules published by the new BCA (off shoot of the BBIA). This included the 1 and 15 in the side stipulation and all shots were slop.
The possible last time Last Pocket 8-ball rules were in the BCA rulebook might be (1982 or so):
http://www.sfbilliards.com/lastpocket8s.gif
Thanks to Bob Jewett. That's the answer to your question. For me, however, I would go to the link someone else put up to get a handle of how others really play last pocket 8-ball.
Fred