Nope - the E-C had a boxy structure there, with potentially one little pimple that could be interpreted as a point-emitter phaser. The model was then pulled apart, perhaps for storage, and reassembled differently for a DS9 appearance as USS Yamaguchi
of Wolf 359 fame, at which point an upside-down Excelsior
shuttlebay was glued under the fantail. A keen eye might spot this bay in a frame or two of DS9 "Emissary", but we don't really see the underside of the vessel in this episode so we can't tell whether there would be ventral phasers in other locations.
Some pictures and analysis here:
speaking of that episode, not to go off topic too much, but they were ridiculously maneuverable in that episode, especially the Ambassador class.