They are fine to use. If they were kept in the dark and away from heat, stored properly, and they were not cut with anything else they should be good indefinitely. They found essential oils in excellent condition in King Tut's tomb. Of course nowadays with technology who knows what is mixed in...
The patchouli I get from Camden Grey is dark brown but does not seem to discolor my soap. I mix it with lavender. The soap is an off white. I think I read in another post where you use EOs from Camden Grey.