Now we are going to have to get a little speculative, but this is necessary. We are looking for any weapon emplacements on the neck and ventral section. Thankfully there are many good pictures from the Christie's auction, and the Negh'Var has been captured beautifully.
First let's look at the weapons in question
in action:

The neck cannon seems to be just below the aft end of the tall section of the neck. Not much is visible on the AGT model:

No visible weapon, hardly any discernible bumps or greebles, besides the sensors which happen to be farther to the front, let alone any yellow trapezoids. So let's turn to the Negh'Var model:

Notice that there are boxes with notches, one of which is perhaps in the appropriate spot for the port neck disruptor. These notches do stick out a little:

.
If this is indeed the case we might count all of these notches, three per side, two aft of the cargo bay door, one fore. There are also notches, albeit slightly different and yellow (the original colour of the disruporemitters) two facing forward, and perhaps two facing rear boxes with grey notches.

The 'phaser trapezoids' are now grey on this updated model, but and whole model seems to be more detailed, although it may simply be lighting. There are however more yellow notches and panels on the model as can be seen all along the model. Should we count some of these as disruptors too? They fore yellow notches on the wing look quite 'intentional' and are elevated on a slightly larger panel of body colour; they are meant to have some prominence. Let us count those in. The large yellow panels differ in shape, they are square rather than rectangular, and do not protrude as far as the larger emitters, nor as far as the smaller 'neck' and wing notches. Let's rule them out. But what of these:

As said in the picture, the bridge notches are very similar in shape to, if not the same as, the neck notches. Some of these notches along the vertical plane of the head are also longer, like the emitters immediately above them. They could be sensors, communication arrays or any other system, but given the similarity to what is our best estimate for the neck cannon from AGT, we can reasonably count them in as emitters, if we are looking for a maximum weapon count. Moreover, they do sport the yellow of the AGT weapons, which may be a hint, though hardly proof.
Alongside these numerous small disruptors emitters, if they are such are also other, more traditional weapon systems, four twin-disruptor cannons. The first two are generally well known:

The second two I recently discovered hiding under the bridge tower:

Of the weapons counted in this round, apart from the seventeen counted in the previous post we can count, at the upper limit two large twin disruptor cannons, two small twin disruptor cannons, ten small disruptor emitters on the neck and wings and aft, four small disruptor emitters on the bridge module (there are more yellow notches but they are smaller and more irregular), and perhaps four small emitters on the vertical plane of the head's 'crest'. That gives us twenty single small emplacements, eight twin-emplacement of the 'older' style, as a reasonable upper limit.

A total, so far of 45 weapon emplacements, 53 if we count the twin-disruptors as two.
Tomorrow, in a final installment I will looks at the ventral weapons