Yes, it is. A positive right is written under positive, or man made law:
law.com
positive law
n. statutory man-made law, as compared to "natural law," which is purportedly based on universally accepted moral principles, "God's law," and/or derived from nature and reason.
The right that anyone has to defend themselves is a natural right. Natural rights are given to us by natural law, or the law of Nature and Nature's God.
law.com
natural law
n. 1) standards of conduct derived from traditional moral principles (first mentioned by Roman jurists in the first century A.D.) and/or God's law and will. The biblical Ten Commandments, such as "thou shall not kill," are often included in those principles. Natural law assumes that all people believe in the same Judeo-Christian God and thus share an understanding of natural law premises.
2) the body of laws derived from nature and reason, embodied in the Declaration of Independence assertion that "all men are created equal, that they are endowed by their creator with certain inalienable Rights, that among these are Life, Liberty and the pursuit of happiness."
3) the opposite of "positive law," which is created by mankind through the state.
What the second amendment does is to give us a SPECIFIC means to defend ourselves (firearms) that cannot be taken away by government.
shall not be infringed
Now the phrase negative right seemed contradictory on its face. Just to be sure, I checked for it, and it isn't listed in any of these On-line Legal Dictionaries, nor is it a phrase I've ever come across.
The second amendment does not give us anything, it protects an existing natural right. It does not say "The people shall have the right to keep and bear arms.". It says the "right of the people to keep and bear arms shall not be infringed", implying that the right exists. And in fact the Supreme Court itself, in Cruikshank has ruled that the right was not created by the Constitution in their ruling that said that because it wasn't, it's not applied by the 14th amendment to the states. (The same ruling indicated that the first amendment is also not applied. That part is no longer "good law".
It's termed, by some at least, a negative right, because what the amendment really does is forbid the government from doing something. A positive right, which is not the same as a positive law but almost, would be one created by law (which includes the Constitution in this context.
Oh and the second amendment says "arms" not "firearms", so keeping and bearing knives and swords, along with "every other terrible implement of the soldier", is also protected.
I suspect that the term "negative right" was coined in contrast to "positive right" which would be similar to a "positive law".