Is Book a collective noun as it has collection of pages?

Collective nouns are an informal part of language. There are hundreds of standard collective noun, but any noun that suits a situation can function as a collective noun. A collective noun is a function of a noun, not a form of a noun.

The standard use of 'book' as a collective noun is 'a book of stamps' or 'a book of matches'. The standard collective noun for the noun 'book' is 'a library of books'.

A 'book of pages' is a suitable use of the noun 'book' as a collective noun.