It surprised me that Cruz didn't bring that up, even more so because Colbert had set up the context of was Cruz willing to compromise on things. Cruz should've used that example from Reagan and said that's why we have to defend the border FIRST!! It makes me nervous, because Cruz hasn't yet renounced his support of even more H1B Visas, instead of filling US jobs with US citizens.
On gay marriage, Cruz took Colbert to school about anything not in the Constitution being a state issue.
Cruz's thing about what he said to his kids about running was contrived, because what he said is not the way you'd talk to children.
I thought Colbert gave a fair although adversarial interview. Cruz was given good opportunity to articulate his views. Cruz did a good job showing his humor and his knowledge of the Constitution, but I don't think he hit it out of the park.
JMHO
In fact, he reiterated it in July: "Cruz: ‘Proud to Defend’ Trump, Expand H-1B Visas For ‘Educated,’ ‘Talented’ Job Creators" - http://www.freerepublic.com/focus/f-news/3309118/posts, July 7, 2015