I have 2 young bps and both are supposed to have the 🔥 gene. Is there a way to tell by looking? The oldest (14 mo.) Is a fire pinstripe, the other is a firefly/od. I read about a head stamp but don't see one on either. At about ten months of age the pinstripe caramel color turned into a metallic gold/bronze color. But it comes every other shed? I've only had the fire fly for two months, so I'm waiting and watching. What should I watch for? Thanks