Uh, no. The one who's uncomfortable here is clearly you, if you have to ask. If you really don't know and it's important to you to 'blend in', then swing by the office in the morning or at night and see how people are dressed coming in or out. Or find the founders on LinkedIn or Facebook and see what they're wearing. Be a little bit less obvious about it.

If I got a note from a prospective candidate like this one, it would probably be a point against them because it broadcasts insecurity and helplessness neither of which is an attractive trait in a prospective employee. This is the part where resourcefulness and self-motivated behavior starts.