This is a slippery slope. As
@Goro stated above, if you have a long history of research, volunteering, clinical experiences, family members in, or some connection to a specialty, I think that stating that you MAY be interested in a certain specialty is ok. I would not state it as an absolute.
As a premedical student, even though you THINK you know what you want to do, you most likely don't. I came into medical school interested in anesthesia, and then I changed to radiology, then surgery, then orthopedic surgery. I had a bunch of experience with anesthesia and was dead-set on it. Things change once you get in and start working through the fields. Things happen in your life (you get married, you burn out, you have children, etc) and you may not want to do that 5-7 year residency that you started out wanting to do (which is certainly fine!). Also, once you get your board scores or see how you match up with your classmates with course grades, this could also change what you are even competitive for.
This is the reason I usually say for interviews, you shy AWAY from stating you are wanting to do a certain specialty and just be broader. The ONLY other situation where I may say that I am interested in a specialty is if the school's mission is to have students who want to be rural family medicine physicians and you ACTUALLY want to do that and have the ECs to back it up, then it would look great to mention that. I wouldn't say in an interview that you want to be a neurosurgeon with zero ECs to back that up, for example.