The original 688's (Flight 1) sat on the surface with the stern noticeably lower than the bow when docked or underway very slowly. At speed the bow are tends to lower itself into the water.
http://navsource.org/archives/08/700/0869610.jpghttp://navsource.org/archives/08/700/0868822.jpgWith the addition of the VLS system for the Tomahawk missiles in the bow ballast tank area, the bow of the (so called) Flight 2 & 3 sit in the water with a bit more level bow to stern aspect.
http://www.navsource.org/archives/08/0875316.jpgThe first 688 to have the VLS was Providence SSN 719, and the VLS hatch configuration (each side has 3 inboard and 3 outboard) is unique to this boat only. The rest of the flight 2 & all of the flight 3 have the 4 inboard, 2 outboard arrangement. You can see the VLS hatches here in the bow area just aft of the sonar dome:
http://navsource.org/archives/08/701/0872101.jpgThe VLS is the distinguishing external feature between Flight 1 & Flight 2. Flight 3 has the VLS and the sail planes were removed and replaced with retractable bow planes. Unlike previous classes with bow planes, these fold in, not up. As discussed before, the Flight 3s (starting at San Juan, SSN 751) also got the 2 anhedrals (which have countermeasure dispensers at their tips) to mitigate snap roll during submerged turns, and the ring propeller for ice operations. Internally, these boats had the new BSY-1 integrated combat sensor suite.
A subtle change was the necessity to relocate the upper ballast tank riser vents to accommodate the VLS system. The screened vents are alongside the hull (see photo)
http://navsource.org/archives/08/770/0877112.jpgAs noted above, the only numbers on the submarine after commissioning are the draft numbers; all hull numbers are painted over.
As noted above by VEPR, the anhedrals on the Hobby Boss kit are woefully wrong. HB does have a tendency to skip detailed research and make s**t up. These is also true of their aircraft kits (almost but not quite right, in several cases).
The correct anhedral installation is highly visible here
https://i.imgur.com/2l2f8No.jpgJust to add to the fun, at least on of the earlier 688's (Memphis) also got the anhedrals, probably as a test case.
Here is a pretty accurate model of a Flight 3 688, complete with anhedrals and ring propeller:
http://navsource.org/archives/08/pdf/0877242.pdf