Not all of them no. In the same way that chicken is free but what you do with it can change the syn value, the basic quorn mince, pieces, fillets and some sausages are free but when you start adding crispy crumbs, sauces etc there are syn involved. Most are relatively small but when you get to the ready meals the syns can be quite high. If you are looking for a particular product it's probably worth doing a search on here as the question may well already have been asked and answered.
It's also worth checking out some of the supermarket own brand meat-free ranges for low syn alternatives.