I don't think that it was originally present on the ground. You would never design that way. I assume that the air loads must offload some of the drooping (and as a result the oil-canning) inflight becasue I have never seen a photo with the oil-canning present in flight --- only on the ground.
The fuselage is built in sections in jigs. The jigs support the fuselage section all around. The seperate sections are mated together. The forward section is basically cantelivered from a ring frame on the aft end. The struture forward of the ring-frame "droops", hence, the oil-canning. The loading is differs when the aircraft is on its wheels from when it is in flight. The last Buff was delivered in 1963. I'm not sure what vintage this aircraft is. The all had a LOT of electronics upgrades while in service. A notable one is readily visible in this photo: The twin FLIR turrets. Origianlly the oil-canning was probably not present on the ground. It may have shown up after a lot of heavy modifications were done forward of the wing/MLG.
It has occured to me that this is the case on AE's Electra and the patch. If, say, the patch was installed with the fuselage tanks empty, and the the deformation may not be present when the aircraft is basically empty. Once the fuselage tanks are full there might be enough flex in that area to load up the "patch" and cause the "puckering". That patch was installed for a reason. I go with the assumption that the section properties of the fuselage in the area of that window turned out to be a lot less capable that would normally be desired, hence, too much flexing under various load conditions (full fuel? hard landing?, etc.). I would wager enough flexing to cause the Plexiglas to crack and the "patch" to be installed becasue, maybe, the material and tooling (an maybe expertise to form the Plexiglas) was not available at an outstation like Miami.
The "patch" did not provide any stiffness to the fuselage at that location. It did not overlap the structure nor did it have enough fasteners to do so. Any loading that perhaps would have casued enough flexing to crack the Plexiglas would show up as a deformation the the "patch".