Greg Jein forgot to put them on his design, so it doesn't have any visible on the model, but one can assume that perhaps they are in similar locations to those on the Galaxy class
They are not on the model. I think the in-universe explanation is that the forward torpedo launcher is located in the neck and that a section slides open to reveal the launcher only when it's in use.
According to the AMT model that I have, the launcher is on the neck. For an image of what it was supposed to look like see: http://drexfiles.wordpress.com/2011/07/03/sotl-2012-1-of-5-tobias-richter/
Admiral William Thomas Riker 17:59, August 9, 2011 (UTC)
Photographs of the original model show a slightly differently colored square just above the main deflector. See http://www.ex-astris-scientia.org/scans/ambassador1.htm. This was covered up later with a solid panel extending up the front of the neck when the model was converted to the Yamaguchi (see http://bruce-domain.blogspot.com/2011/09/other-ambassador-class-starships.html)