Plural

He ordered the first and third cars built.

What does this sentence mean?

I do not know the context.
I was only selecting the better sentence.

Perhaps it is about an automobile manufacturer, such as Henry Ford?
Perhaps he was more personally involved with the first and third car models that the company built?

This expression is from a forthcoming book about a limited production Maserati.

I am now thinking that it should either be

He ordered the first car built and the third car built

or

He ordered the first and third cars built

Your second option:

He ordered the first and third cars built.

Was my answer in my first reply to you. )