I think that in these times it doesn`t matter so much (or it shouldn`t) I mean guru gobind singh declaired that to be a true desciple you have to have kangi, kachh, kard, kes, and kirpan, most sikhs don`t carry all these things with them and they`re still sikh. Almost every sikh guy I know has short hair, and it doesn`t make them any more or less religious.