Howya Kevia,

Just ta prove that I'm not just a cute face, I dug this up fer ya from the bowels of me brain:

Also know as a stab in the dark.
An act whose outcome can't be foreseen; a mere guess.
Metaphorically use of dark = in a state of ignorance and dates from the late 17th c.
Cowper used "shooting in the dark" metaphorically in Mutual Forbearance (1782) but a shot in the dark is not recorded before the late 19th c.

Hope this answers yer query

GallantTed