Exactly like the title says, do silver gauntlets count as a weapon and do damage for the purpose of lycanthrope immunity to non-silver, non-magical attacks?
Gauntlets ARE mentioned under various Armor types (Scale, Chain, Plate) in the PHB 144-5. Whether or not your DM will allow silver plating on those or armor of silver will be table dependent.
As weapons, Gauntlets are not listed in the 5e weapon list in the PHB on page 149. However, you may be able to do an Improvised Weapon which would deliver 1d4+STR MOD (PHB, 147-8) of damage bludgeoning (Pending DM approval). If they were made of silver, then it would bypass the immunity.
Otherwise, the attack would be from Silvered armor, if allowed from above, and deliver an unarmed melee attack for 1 bludgeoning damage that would bypass immunity from the silver.
This becomes entirely up to you and your DM :) But it'd be a difficult argument to say they wouldn't bypass the immunity.