I would ask. If it is a private party most won't care. I brought my pup last Sunday out with Brad B's outfit. It was me, my son and the guide. I "expected" my dog to do well but it was his first time to hunt ducks for real (hunt test don't count) so you never know. It went great but I would have been nervous in a mixed group since it was his first time.
BTW - Thanks Brad again we had a good time
Funny Story - I did have a guide tell me that the dog has to be run flawlessly, that is why the only bring there own dogs. The guide I hunted with had a lead on his dog that he stood so the dog couldn't break and then couldn't handle a blind retrieve. Even better than that is the video on the website has a different dog already in the water before shooting has even stopped.