I think your summation is accurate and correct.
I reviewed Hawaii’s electoral votes in 1960 after this.
In that case, there were THREE “certified” sets of electors, one from the Gov made before the recount showed Nixon won (for Nixon), one from the GOP electors based on that; and one from the JFK electors based on the official recount.
So there was a certification difference in the official slates that were submitted.
Nixon, as veep, merely accepted the latest official certification. He did not rule on the legitimacy of either electoral slate.