I'm not sure if you ever got the answer to your question, and considering it was so long ago I'm sure you have. I'm in Florida and I breed both meat and show Silver Foxes. Right now they're trying to get blues accepted in shows. As long as the rabbit is black it is able to be shown. However, to help out your customers, so they don't get point deducted at the show, the best thing to do is 1. Make sure they have a great temperament, which I've never seen an aggressive SF and 2. Make sure their nails are black. Black nails show that they are true SF lines, usually if they have clear nails they were from the lines that were trying to get Silver Foxes long ago by mixing breeds. I try to always sell black nails as show ones unless the person is 100% stuck on a certain rabbit and understands that they can be deducted points in show