The aircraft in the photo has a clipper bow, I get the impression from reading that a clipper bow means the turret has been removed and the resulting "hole" has been faired over. One statement found,
One thing that civil PBY conversions accomplished was a necessary bit of beautification: what came to be known as the “clipper bow,” a fairing-in of the cowl ahead of the windscreen to eliminate the awkward nose turret. If there was one discordant note in the Cat’s refrain, it was that squared-off little greenhouse that gave the airplane the look of an angry hognose snake, a protuberance that seemed an add-on and if anything harked back to World War I observation airplanes with a freezing Frenchman standing upright in the bow. On early PBYs, in fact, the “turret” was indeed nothing more than a semi-open bombardier/observer’s post. Guns came later—ineffective single or twin .30s in the nose, single .50s in each waist blister and sometimes a .30-cal firing from a belly hatch near the tail.
The awkward nose turret. You can appreciate the different sight lines a pilot would have in the two versions.
