Yeah just maintain good manners, like you wouldn't be always interrupting and finishing the sentences of a person without a stutter...I should hope!
My husband has a kind of phantom stutter that only shows up when he's stressed, so on the phone, public speaking, negotiations with bosses at work etc. He told me this on our 3rd date or so. I said I had never noticed. "Well luckily it doesn't happen around people I like" Cute line for a date but I know it causes him pain. Since he can hide it most of the time, many people don't know he has it, until a critical moment but then they're less likely to be understanding since they don't know about it. He's been teased and even offered glasses of water because people thought he was choking omg. I personally think he ought to be more open about it because when people know, they're more understanding, but he's had it since childhood and so far he chooses to deal with it this way.