The description of the Gloves of Thievery (DMG, p. 172) says:
These gloves are invisible while worn. While wearing them, you gain a +5 bonus to Dexterity (Sleight of Hand) checks and Dexterity checks made to pick locks.
The Arcane Trickster rogue's Mage Hand Legerdemain feature (PHB, p. 98) says:
Starting at 3rd level, when you cast mage hand, you can make the spectral hand invisible, and you can perform the following additional tasks with it:
- You can stow one object the hand is holding in a container worn or carried by another creature.
- You can retrieve an object in a container worn or carried by another creature.
- You can use thieves’ tools to pick locks and disarm traps at range.
You can perform one of these tasks without being noticed by a creature if you succeed on a Dexterity (Sleight of Hand) check contested by the creature’s Wisdom (Perception) check.
In addition, you can use the bonus action granted by your Cunning Action to control the hand.
Technically the gloves are on the hands of the character, but would the bonus they provide also affect the additional actions you can perform with this special feature granted by being an Arcane Trickster?