I've been looking for information on when the Selectric II and Correcting Selectric II typewriters were launched. As I had expected, not much time elapsed from the time IBM announced the Selectric II typewriter and the announcement of its successor, the CORRECTING Selectric II typewriter. I don't tend to see too many non correcting Selectric II these days. Once the ability to correct errors was available, I'm sure lots of early Selectric II's were traded in for their successors.
Here's the announcement for the Selectric II. This comes from the Kingston Daily Freedom, September 13, 1971.
Less than a year later, IBM announces the Correcting Selectric II typewriter as seen in the March 4, 1973 Edition of the Poughskeepsie Journal.