I don't know about the coloring but maybe once the lady has seen them she might know if that is what she is looking for.

My roommate in college had a calico that died and she wanted to get another calico. I helped her look for months until she found a true calico that fit the bill. For her, the look was that important and nothing else mattered. My roommate was a great cat owner and I would have no qualms about her adopting another. Maybe this lady is like her, just looking for a certain look but no less a good pet owner.

It's also good to go with gut feeling sometimes.