The available models in N of these locos are the as-built wartime versions. They were extensively modified on the roof and sides after the war, specifically removing all the as-built roof vents and moving and changing the dimensions of the side "windows". I've tried to scope out the new side vent placement and dimensions from photographs but it's not the best way. I'm wondering if anybody has knowledge about these modified 109s as to the new openings, or possibly a close-up full-side photo view of one of the modified locos (regardless of paint scheme).
There is some info, mostly on roof modifications (incl a roof diagram) in the trainweb link below. It also references an article by Robert Vancour from the 1980 Shoreliner - perhaps someone from the NH Historical Society could provide you with a xerox or pdf, or other more current articles/back issues on the subject? http://trainweb.org/csg/proos/NHDL109.html https://www.nhrhta.org/