Do not automatically change an initial wāw to hamzah. Identify its vowel and determine whether the book describes an optional environment or a specific attested case.
ExampleInitial vowelStatus
وُجُوهٌ → أُجُوهٌḌammaPermitted
وِشَاحٌ → إِشَاحٌKasraPermitted
وَحَدٌ → أَحَدٌFatḥaSpecific transmitted form
وَنَاةٌ → أَنَاةٌFatḥaSpecific transmitted form
A similar-looking spelling change does not necessarily have the same morphological reason.