Do you think one should know about the product they are selling incase a customer asks questions about the item?

You should definitely know as much about your products as possible so you can offer wonderful customer support and set yourself apart from the competition =).

If you are thinking about doing a niche that you don't know a lot about/ don't want to learn about then I suggest that you find a different niche that isn't so info heavy. The thing that will set you apart from other drop shippers is your customer support and if you can't answer your customer's questions then they will go to someone who can.