original name of India

"Hindustan" a name for India - to the best of my knowledge - originated with the Mughal empire in the 1500s, after Columbus arrived in the Americas. While "Hindustan" as a English word seems to be post-Mughal, it has earlier cognates. This doesn't particularly help Carlin's case though. Check out this post for more.

Did Columbus write or say "In dios" (en dios)

I'll quote Columbus in his letter to King Ferdinand (translated into English of course; emphasis mine):

SIR: Since I know that you will be pleased at the great victory with which Our Lord has crowned my voyage, I write this to you, from which you will learn how in thirty-three days I passed from the Canary Islands to the Indies, with the fleet which the most illustrious King and Queen, our Sovereigns, gave to me. There I found very many islands, filled with innumerable people, and I have taken possession of them all for their Highnesses, done by proclamation and with the royal standard unfurled, and no opposition was offered to me.

To the first island which I found I gave the name "San Salvador," in remembrance of the Divine Majesty, Who had marvellously bestowed all this; the Indians call it "Guanahani." To the second, I gave the name the island of "Santa Maria de Concepcion," to the third, "Fernandina," to the fourth, "Isabella," to the fifth island, "Juana," and so each received from me a new name.

Columbus called the Taino "Indians" not because he thought he was in India but because he thought he was in the Indies (Indonesia).

Was 1970 the first year the term native American was used?

No. The first time the phrase is used to definitely and solely refer to indigenous Americans / American Indians is when the Native American Church forms in the early 1900s.

One thing Carlin does get right though - if you know a person's specific national identity, that's preferred. Though it's weird that Adirondack is his first example, considering you're never going to run into someone claiming to be an Adirondack. They're an old Algonquian nation that used to live in upstate New York (hence the name of the mountains there), that were dispersed by / absorbed by the Mohawk in the late Pre-Columbian / early Contact era according to Mohawk oral history.