The external signs of weapons emplacements on a battle cruiser are basically nonexistent, save for the torpedo tubes. Sure, the phaser pimples on Federation ships are tiny, too - but the Klingon vessels don't even have a specific design for a weapon.
The "turrets" at the stem of the hull boom look more like the Phalanx CIWS guns of current USN warships, in placement and design both. Naturally, all incarnations of the physical model from TMP on feature them, but they are never seen firing, so we might just as well assume they are secondary, defensive weapons that have no offensive uses.
The similar "gun" greeblies at the bottom of the bow flarings are never seen firing, either, and could be further CIWS emplacements. The four emitters put together would give good CIWS coverage for the forward hemisphere; further greeblies next to the aft top structures ("intercoolers"?) may take care of aft threats, even if they aren't identical to the other four turrets.
Heftier greeblies are to be found at the bottoms of the forward corners of the wing structure. These don't match either the TNG mid-wing disruptors or the TOS nacelle-tip ones, though.
Perhaps the main guns of these ships are less standardized than the secondary ones, due to being more important in combat and in giving the edge to a particular House against another? It is difficult to accept that the placement of "main" weapons would be more easily altered than that of "secondary" ones, though: how small are these heavy disruptor banks supposed to be? Invisibly small?