Quite frankly, it's better to underplay your skills and impress people then to exaggerate and disappoint.
My favourite memory of this is a long stream of candidates answering job postings which specified "experience with Unix and Linux systems" in the required skills. If you are going to put "extensive experience with Unix and Linux" on your résumé, then you should, at the very, very least, be able to name at least one Unix variant.
And "uhhhh..... Red Hat?" doesn't count.