Marek,
First off are you planning on building the LIVERMORE more or less straight from the box in a mid-late 1942 configuration with six 20-mm guns? I will assume so in the images I'm providing. The ventilation on the BENSON-GLEAVES dual-class was an issue throughout their career as far as I can tell. With the addition of a larger crew and more equipment (electronic being a big problem) the as built ventilation went through many changes as you have noticed. Also, the heavy seas of the North Atlantic caused many problems with water entry and different styles of vents were tried. Most vents on the forward part of the ship had doors to shut them off in bad weather, but this caused additional problems. So yes, the location and type of ventilators do vary. The early group of units (DD421-444) should be treated separate from the repeat units in many cases. But, some of the ventilation modifications were applied to ships across the groups. Some "styles" of ventilators were associated with a specific yard. If you are interested in modeling a ship at a specific timeframe and have limited views of that ship, try finding views of near sisters from the same DesDiv/DesRon if possible, because in my experience with this class ... they are MOST likely to be the closest. It does NOT work in every case, but is a good place to start.
The vents along the deckhouse on the main deck amidships is really an example of evolving ventilators.
If I have not addressed the period of interest of your build, let me know and I can try to find views for that time frame.
Below are a series of views of Bath Iron Works built GLEAVES class destroyers from the pre-war group.
USS GLEAVES (DD-423) as completed 27 May 1940. Note the use of mushroom vents.

USS NIBLACK (DD-424) as completed 16 July 1940. Note the mushroom vent and two vents of a different type with doors.

USS LIVERMORE (DD-429) after she was modified with six 20-mm guns replacing the 0.50-Cal MG's on 11 May 1942. Note that the mushroom vent has been modified to, I'm guessing, keep the water out from the front and seaward sides.

USS ERBELE (DD-430) also after she has received her six 20-mm Mod on 12 June 1942. Both ships were modified at Boston Navy Yard. Note, same type mushroom vent as used on LIVERMORE.

USS WOOLSEY (DD-437) on 2 February 1942 showing the top view of this revised mushroom vent. Looks to be a simple "ring shield" mounted around the original mushroom vent to help block off water entry.

USS LIVERMORE (DD-429) after she received two twin 40-mm mounts on 5 June 1943 at New York Navy Yard. Not a real good view, but the vents have been changed to completely different types.

USS LIVERMORE (DD-429) a couple of months later on 4 August 1943 showing the quite different design of the vents on the portside.
