I've stuttered a little during every interview I've ever had and I've been employed for 20 years. The hiring manager might specifically call out that you will be expected to interact with customers, but it would be a violation of the ADA to discount you from the position on account of your speech. That said, you'll be in a position where you'll be exposed to a lot more people and forced to speak to them. Unfortunately, some people are rude and you might run into the occasional jerk who says something like "what, cat got your tongue LOL"? but that's bound to happen eventually just because people are people. Look at it as an opportunity to practice your fluency, because that's the only way it'll ever get better.