Sorry this is a little late. I've had trouble getting through.
>> But when Popper described it as "unfalsifiable," he did not yet have
the categories of "paradigm" and "research program" available to him. (**)
Those categories were later contributions of other philosophers of science.
<< >> (**) Someone please correct me if I have the chronology wrong. <<
Well, remember, you asked. ;-)
"Paradigm" is generally associated with Thomas Kuhn's _The Structure of
Scientific Revolutions_ (1962). "Research program" (metaphysical?) is more
difficult. Popper states he used "metaphysical research program" since
1949. His description in print was to be published in 1956, but he had
health problems, and the galley copy were not printed until 1982. However,
he had distributed the manuscript to students and colleagues; the term was
discussed at length at a 1965 conference where his views on falsification
were compared to Kuhn's paradigms. The papers from the conference were
published as an excellent book, _Criticism and the Growth of Knowledge_ in
1970; the editor of the book renamed the phrase to "scientific research
program" in his own paper to remove ambiguous interpretations of
"metaphysical." Popper's autobiography was published as part of a series
on him in 1974, and as a separate book, _Unended Quest_ in 1976; this
contains the "unfalsifiable" statement. Popper's "recantation" appeared in
1977. I'll leave it to you to compare the dates. :-)
Don Frack