My other buck Sage does carry self.
I do think the steel must be coming from her side too, I looked all through his pedi, and there's no steel. The lines that he came from are out of a breeder who's been in the breed for around thirty years, and knows her stuff (incidentally the one who would take him in a heart beat, she sold the parents to the lady I bought him from) and she would have put it on the pedi if they were anything apart from what they looked like.
The first time I bought a rabbit from her directly, and I told her I had Oliver, she told me that in his pedi there is one buck (Oliver's great grandfather) that was listed as a black, that was actually a seal, but she was using his registered color. The registrar was color blind and before she could notice it to change it, he'd been registered as a black.
She must just have the modifiers to throw those self colored steels though, because all of her last litter looked self, and all but one out of this litter do too.