Here is an article from August of this year, reporting that the first vehicles (not parts) were rolling off of the production line in Ohio:
http://money.cnn.com/2015/08/13/news/companies/ford-truck-mexico-ohio/index.html
If the line was already up and running in August, then there is no way that Trump’s rhetoric had anything to do with the move.
In August Ford was still planning a move to Mexico.
Trump hasn’t claimed to have contributed to Ford having built plants in the US previously.
I was wrong on the parts thing, it was trucks. But, from what we now know, Ford will not build in Mexico, but also make cars in the USA. So, no, that doesn’t mean that Trump didn’t have anything to do with this.