Airframes were rebuilt and strengthened for the new engines,has a different,longer nose (about 30cm) and wingspan is 14.2m.Wings are not only longer,they have greater surface too.Last aircraft,designated R-222,delivered in 1996 with the new timeline.
It sounds plausible, and such an aircraft could be kept in service up to the early 2000s, but it would be functionally obsolete as a front-line strike craft. At that point you could consider something like a Rafale as a replacement (also dual-role replacement for whatever front-line fighter would be due up for retirement).