In theory, yes.  In practice, some packages completely leave it out, some packages put it under "license" and some under "licenses", and many packages don't bother to include the license text with the code.  I've filed dozens of tickets with upstream NodeJS projects to improve these, most of which have been ignored for years.  I've come to the unfortunate conclusion that the NodeJS community in general can't be bothered with license details.

-Jared