Yes, while simple genetics will tell you there should be a homozygous animal that looks identical to the heterozygous animal, so far we have not seen it. Does that mean it doesn't exist, no. But as of right now, very very very few people claim to have a homozygous pin or spider, and even then, they are not blaring the news across the internet for all to see. It could be they just hit amazing odds (all pins in a clutch). I have a clutch of 4 eggs sitting in the incubator from a spider to a normal. If I hit all spiders in those 4 eggs, it could be that I have a homozygous spider.....or it means I hit good odds. That is why anyone that does hit those odds, must then breed that animal for several more seasons to prove out if they are indeed a homozygous animal. And in the 10+ years these animals have been in the industry, you'd think more people would have homozygous animals, especially if the chances are a whopping 25%! The chances of hatching out an axanthic killerbee are less, and there is proof (pictures) of those existing.

I was actually thinking of taking some spiders and pinstripes and breeding them for the sole purpose of trying to find a homozygous animal. It would take years and years, and in the end might result in nothing. But it could be fun to try. Who knows.