You won't be able to make a direct copy of the whole headlight since you need a flipped version for the other side, but you could at least mold up the headlight by itself and maybe use some brass/copper rod for the part it sits on
Considering the headlight itself it is such a simple shape, I might use some Oyumaru to make a mold as you don't need anything that involved
it is a reusable mold making material that you let sit in near boiling hot water for a few minutes, then squish it around what you want to make a 2 part mold of. Then you can use Green Stuff or Milliput (or other 2 part epoxy type of material)
All fairly cheap stuff
the Oyumaru you can find on Amazon as well as other places. Same with milliput