It's true that sometimes one cannot tell if a Jack will have a rough coat or smooth coat. Not always, but a good part of the time really. By the same token, my Annie's ears layed down as pretty as your best classic Jack at the first, and now they stick up (called prick ears)3 inches straight up!
It is possible for 2 rough coats to produce a smooth coat since somewhere in their genetic make-up there had to be some smooth coat genes.
I guess Jacks can be sometimes like a box of chocolates...you never know what you might get. But mostly, depending on the breeding of the parents, you can predict a pup that will be very similar to the parents.
