I'm not so sure, really. When I first went into the AFCO I was wearing a pair of old jeans and some issue boots I was attempting to break in, a mountaineering type jacket and a dirty faded daysack over my shoulder. I really don't think the first trip into the AFCO has an impact if it's just (not to be derogatory) the desk staff you're speaking to, after all the P2 presentation is the first real part of the selection process.
From my experience, go in there, don't fret about it as you're not being judged (in any way that's going to make a difference, at least). It was evident I didn't have a scooby when I first walked in there, but I don't suppose they will expect people to, as long as you know your stuff for your Interview you should be fine. Let us know what happens!