I watched the whole Back to the Future trilogy this week and I just happened to think of something.
The Delorean ceased production in 1983. Doc fitted it with the flux capacitor and other add-ons in 1983. It had a hover conversion and a Mr. Fusion upgrade in 2015. After Doc went back to the old west and Marty and the Doc found it in the mine, they had to give it new tires and replacement parts in 1955. Then back in 1885 it was further modified to have wheels that could work on the train tracks.
Assuming it's a 1983 production model...
It's a 1983, 1985, 2015, 1955, 1885 DeLorean. It's quite the Frankenstein's monster.