In the contests I have submitted to - (don't know if this qualifies as a real publisher) - the ones who have stated a preference have asked for Times New Roman, 12, double-space, (unless it's poetry). One publication said either TNR or Courier. One inch margins are standard, and I don't know what gutter is.

Agree with Westerly. The publishers (as opposed to agents) who will actually look at unsolicited proposals and manuscripts -- and I don't think that is every one, or even more -- I believe state that on their websites.

Since gutter is the extra space in the margin on the binding side of a page, gutter probably won't apply to your submissions.

Unless otherwise specified (see the web page for each publisher) they want loose leaf.