No, guy is not gender neutral.
https://www.dictionary.com/browse/guy
https://dictionary.cambridge.org/dictionary/english/guy
https://www.thefreedictionary.com/guy
https://english.stackexchange.com/questions/11816/is-guy-gen...
Note that wiktionary points out the fact that the female complement to "guy" is "gal". https://en.wiktionary.org/wiki/guy