In previous Elite's big ships like the Anaconda did have turrets that could fire 360 degrees around the ship but, of course, a top turret could not fire below a plane and a bottom turret could not fire above. This gives some potential gaps in fire that a Cobra could take advantage of.
The question though of Cobra vs Anaconda depends a huge amount of settings and setup. In general and small ship (Cobra on down) should indeed be wary of an Anaconda since they have the potential to have mounted some serious gear and output high damage at range.