This announcement article from August of 1965 indicates that both the SCM Cogito 240 and Cogito 240SR electronic calculators were introduced at the same time.
Other information suggests that the Cogito 240SR may have been introduced
slightly (perhaps a couple of months) later than the Cogito 240, however,
nothing has yet been found that definitively indicates if that is the case.
It is positive, though, that by the Fall of 1965, both machines were being
delivered to customers.
