Yes, silver is more dense, and gold even more so. But seriously, nobody in Iron Age Finland would have so much silver laying around that they would waste it on a mace-head and then damage it in combat, especially not a 16 year old kid that just left home. Why not do a reality check here before putting time into mods that are out of the scope of reality.
I'm also saying this because aside from it only being "realistic" in Dwarf Fortress, this kind of fantastic wealth is against the intent of UnReal World. Just a casual look at how the devs have made the game's valuables & trading system makes that obvious, doesn't it?
I think all the wealth owned by all the NPC's would hardly account for one gold mace. Who could possibly barter it from you?
All that said, of course, I'm not trying to stop anyone from modding whatever they want. Go for it. But claims that those precious metals are good for anything other than ornamentation on prize weapons need to be refuted.