It wasn't so long ago that I was in your position, hoping an employer would take a chance with me....
Almost all of my own Unix knowledge was self-taught by reading and by playing around on various Unix systems. If you are comfortable working with computers, you will probably be able to get up to speed as an intermediate Unix user pretty quickly, especially given your previous exposure. You will have to put in the time to do some reading, and of course have a machine you can access to practice and explore as you go...
As for the job, I think you should be honest with the potential employer about your skill level...you may find that they are willing to send you to a training class to get you up to speed. On the other hand, they might need someone who has more experience...it would be better to find out now, than 3 months from now in the CIO's office!
In summary: Go for it, be honest about your skills, but also be honest about your eagerness to learn...

Good luck.

[Edited by PxT on 11-21-2000 at 06:16 PM]