GF are a bit inconsistent when giving genders to non-legendary pokemon, although there seem to be some general patterns.
All genderless non-legendary Pokemon are in the mineral egg group (Beldum, Baltoy, Bronzor, Cryogonal, Voltorb, Golett, Klink, Lunastone, Solrock, Magnemite, and Porygon lines) with a few exceptions (Ditto, Starmie, Unknown, Rotom and Shedinja). But, in the mineral egg group you also have the Geodude and Roggenrola lines (and a few others) that do have gender even though they also are based on inanimate objects.
In the amorphous egg group you have most of the ghosts and many of them do have gender. To point out some of the inanimate Pokemon in this group we have Banette (possessed doll), Gastly (possessed gas) and Chandelure (possesed chandelier) which all have genders.
I guess this means Honedge will most likely be in the Amorphous egg group (as a ghost with gender). Although it wouldn't suprise me if it also is part of the mineral egg group, just like Yamask and Cofagrigus (both of which have genders btw).