Testing versus the lion paws, the knuckle-dusters seem to do a little bit more damage.
While the claw attacks of the lion paws do more damage generally, the lion paws always have a slew of unimproved punches with them which lowers the average damage per hit while using them. The knuckle-dusters only do punches but every single punch hit is boosted by the dusters. This creates the situation where the knuckle-dusters are doing more damage on average. The difference is pretty minor (5hp) but with knuckle-dusters weighing less and using blunt damage (which is better vs trolls and armour) they therefore seem an improvement over the lion paws. They also appear to do more damage than the squirming black tentacle (which does less than the lion paws). I have spoken to another experienced unarmed user and she mentioned that the leather-strap gloves do less damage with base attacks than knuckle-dusters but have better special attacks. With 591 bonus is striking I had an average damage of 226hp per hit with the knuckle-duster punches. The lion paws average damage per hit (including claw and punch hits) was calculated to be 221hp per hit.
There is very little difference though and it might be up to the player to choose between consistent good blunt hits or some higher damage sharp hits mixed with lower damage unimproved punches (with damage spikes and lows).
Also note this research was done with a stat item in one hand, by having both hands free it is possible that the lion paws would have more claw attacks and trump the knuckle-dusters in terms of damage if both hands were free. - Toffee 04/07/2020
A limited test between knuckle-dusters and leather strap gloves with punch attacks in fact showed similar damage ->
Leather strap gloves
863 924 943 890
860 920 960 933