When can a newborn use and wear non hospital clothes.?

I'm pregnant with twins, and my husband will be deployed so he wont be here. I was wanting to take lots of pictures of the babies in the hospital, but I want him to be able to tell them apart. So I decided I wanted to bring a pink hat and a purple hat. Can the babies wear these as soon as I give birth, or do they have to wear hospital stuff first. I don't have a dr appointment for 2 weeks and I want to know asap so I can figure something else out. Thanks in advance!