Most Helpful Guy
As a general rule, I would say take it out.
These sorts of things tend to be given as unwritten societal rules, but people get judged for not knowing or not conforming to them. Much like wearing a suit to an interview.
However, since this is just an agency and you plan to bring it up with her anyway, that might be more acceptable. If you were to say nothing, the woman might just note in the file something like "No customer facing applications." and leave it at that, but it would restrict the sorts of positions they'd put you in for.
But by bringing it up to her, you're letting her know that you are unsure of the situation, and implying (at least I hope) that you'd be willing to compromise your facial fashion for a job.