Oh, and I guess Barr wouldn't win by default, anyway: Ralph Nader made the cutoff as a write-in candidate.

§ 192.031. PARTY CANDIDATE'S ENTITLEMENT TO PLACE ON BALLOT.
A political party is entitled to have the names of its
nominees for president and vice-president of the United States
placed on the ballot in a presidential general election if:
(1) the nominees possess the qualifications for those
offices prescribed by federal law;
(2) before 5 p.m. of the 70th day before presidential
election day, the party's state chair signs and delivers to the
secretary of state a written certification of:
(A) the names of the party's nominees for
president and vice-president; and
(B) the names and residence addresses of
presidential elector candidates nominated by the party, in a number
equal to the number of presidential electors that federal law
allocates to this state; and
(3) the party is:
(A) required or authorized by Subchapter A of
Chapter 172 to make its nominations by primary election; or
(B) entitled to have the names of its nominees
placed on the general election ballot under Chapter 181.