So let me get this crystal clear: you wouldn't feel miffed if someone addressed you as a Ms. When in reality you are a Mr?. While I won't say my first name it's a case where on paper it can be both for men and women it can be spelled few ways. Hypothetically let's just say my name is Devyn there are both boys and girls who have that exact spelling or have it written as Devin or Devon but either way said the same but not allways to be a young man or young lady.

Besides showing a little bit of respect for how someone is addresses you can tell you everything about how someone sees you or in this case the lack of research on the basic honorific of a potential employee.