Exactly, I think a strike surface of 40 is more like a cartoon boxing glove. I think giving a knuckle duster the same contact surface as Lucas Cranach's warhammer is probably fine, which I think is 10. If you wanted to simulate the type of knuckle dusters with points instead of blunt edges, you could just make the contact surface 1 like a whip.
I'm actually not sure if the speed between swinging a sword and punching with your knuckle duster would be all that different. Like, a knuckle duster could probably make quick jab attacks faster than a sword could, but you wouldn't do much damage with that kind of attack. For a full power punch, I think you'd be exerting as much energy as you would for a sword swing. (more or less the same with hammers and axes too, I've seen HEMA youtubers express that historically accurate hafted weapons aren't very clumsy) But if you prefer more of a video game balance instead of reality, then I could see knuckle dusters having less damage but more speed.
Also fun fact from the wikipedia page, US Civil War soldiers were concerned about fighting hand-to-hand, so they either bought brass or iron knuckle dusters or they made their own by melting bullets. Wouldnae that be cool for a dwarf?
I'm glad you necro'd this topic though, I'm having fun. Hopefully someone who tries to mod in their own knuckle dusters 20 years from now will search this topic and know what to do.