In addition to FuzzyBoots's answer, some other details about the original novel.
The adventure in the Land of Toys happens in chapters 30 to 33 of "Le avventure di Pinocchio". In these chapters, Carlo Collodi uses the word "ragazzi" all the time. As Nolimon said in the comment (and FuzzyBoots's reported in his answer), in Italian "ragazzi" may mean both "boys" or "children/kids", depending on the context.
Are they all (or mostly) boys? Possible hints
Other parts of the book explicitly mention boys and girls
In Chapter 10, Collodi explicitly says that the puppets in the Great Marionette Theatre are both male and female:
Quei poveri burattini, maschi e femmine, tremavano tutti come tante foglie
Those poor puppets, male and female, were all trembling like leaves
Later, when Pinocchio is turned into a donkey and works at a circus (Chapter 33),
Le gradinate del Circo formicolavano di bambini, di bambine e di
ragazzi di tutte le età
The Circus terraces were swarming with little boys, little girls and [boys|kids] of all ages
On the contrary, Collodi never explicity says "boys and girls" in the Land of Toys, so we may speculate that they are all boys.
This is kinda weak (and may be viewed today as sexist), but another possible hint may be the games the children play in the Land of Toys (Chapter 31). Most of them look like "boy games" (at least for that era). E.g. nobody is playing with dolls. My wife adds that the overwhelming volume of the noise suggests they are (all or mostly) boys.
Illustrations included in a book are not necessarily canon, but the oldest ones were drawn and published when Carlo Collodi was still alive. In this illustration by Carlo Chiostri, the most clearly visible kids look like boys. Again, this is only the coach, it may not be representative of the full population of the Land of Toys.