The question is quite simple. Do hiddenSelections work on weapons for retextures? It doesn't seem to work, but I am not 100% sure that I did it right. In any case, the token is only listed in the CfgVehicles section.
If not, I am going to make a feature request ticket for it. It would be much easier to maintain a pack of weapons in different camos if you would only need one complete set of models and could do the rest via hiddenSelection.