As far as I know, the colors used for text, background, selection and friends are not exported by iTerm so what you want is out of reach.
Instead, use the same color you used in the settings window, converted to its nearest neighbor in the xterm palette.
Also, you are supposed to use ctermbg
and ctermfg
as guibg
and guifg
are, obviously, for GUI Vim and thus wrong and useless in your situation.
Example:
hi Visual ctermfg=16 ctermbg=67