Was Rambo part Indian?

From correspondent Al Carroll:A lot of reviewers noted that Rambo seemed to be playing Indian. Never heard of any source claiming he actually was supposed to be.

I haven't read the book, but have seen online discussions that describe it as being quite different from the film series. The book version has him as a scrawny, timid man still in shock, acting purely ouf of panic.

The only scholarly discussion I've ever seen of Rambo is David Espy's article. Espy calls him a "symbolic half breed."