I do not EVER remember a repub leading in the polls. It is ALWAYS a dem leading by HUGE margins.
Polls showed Nixon ahead of Humphrey in 1968 until they tightened considerably in the last week before the election.
I don’t recall any polls pointing to a Mondale victory in 1984. And they showed that GHWB pulled ahead of Dukakis by Labor Day, with the Al Gore-instigated revolving door video.