I could have said, "The 78 Datsun 510" but realized, if he was not acquainted with such a wonderful vehicle, this would mean nothing and could be off putting.
Whereas "the brown Datsun wagon," was simpler, straight-forward and opened the door for him to exclaim "Oh, wow, a 510 wagon - what year - my brother once owned one and he........"
However that door never got even a chance of opening. It was only later that I followed an alternate conversation. (It is one form my writing takes, this dialogue with self, after the fact.)
At the time I pointed with my free arm and said, "It's the Nissan."