Well I know this is an idiot question but it's just because I really don't know the answer. I always look at her A Song for XX cover and wonder about that. I always look for pics after the release of it but they all have ayu wearing pants or long boots so I'm never sure. I even downloaded a high quality version of the LOVE ~Destiny~ PV cause it shows her legs but I still couldn't see it clear.
That also looks like some sort of paint but well I'm not sure. I never see anyone commenting about that also. I know it doesn't matter at all but if anyone knows I'm very curious.
Source of scan:
http://ayumi.primenova.com