If they set the stud fee at $25k or more---they will absolutely announce that his book is full and closed. Because they have to! If they don't, the entire market will know the farm couldn't get other commercial breeders to support and breed to this horse. So announcing that his book is full and closed means zero. Less than zero.
You have to have a copy of the syndicate agreement and understand how modern day syndications work. If his stud fee is set at $25k or more, bet your last dollars that at the end of the second (breeding season) year---even if, and it's a mostrous even if---even if he bred 120 mares, check two things. One get a list of the mares bred. Two, look at the pooled stud fee(s) distributions. You will see a fraction of the 120 mares actually paid the advertised stud fee.
No Nukes and Jate Lobell are just two of the reasons why modern day syndications are very, very different than all those years ago.