It actually doesn't depend on when it was said. It was wrong. But, for the record, he said it in October 2016.
It seems to me that the Republican establishment didn’t support Trump but that he was able to rally his base in order force their support begrudgingly.
I believe the term that Trump’s base used for those Republicans was RINO, Republicans In Name Only. So the fact that this vocabulary existed among Trump’s base to me indicates that their support for Trump was not automatic.