Howdy,
I found out that a cutlass can not be imped even though it shows the imp column with the item associated.
Examining the item does not show the possibility to imp it
Not sure if these are intended to be imped or not, but as it says above. Activated iron lump, right click, no option to imp. The examine info also doesn't say that you need "x item" to imp, but there is an icon for it in your inventory.