Yes, addition of a weight distribution system can with a compatible and properly-rated trailer hitch receiver result in an increase in that hitch's tongue weight and/or gross trailer weight capacities. The safety/warning sticker on a hitch will indicate if it is rated for use with a weight distribution system and what the increased ratings are when one is installed.
Some vehicles themselves may also have increased tongue weight and/or gross trailer weight capacities when a weight distribution... view full answer...