In my experience working at a call center, they are likely only looking for any big deal-breakers when hiring you. A stutter absolutely should not be a deal-breaker, but any hesitation from you at being able to do the work *due* to a stutter absolutely can be. I'd disclose it if it comes up in conversation (e.g., if I blocked on a word in the interview). Like, no, I'm not confused, I just have a stutter! I'd be genuinely surprised if they flagged it unless you expressed any doubts. As for general interview advice, be prepared for normal interview questions, but give a little "thinking pause" to collect yourself after each question even if you're prepared for it :)