Actually the Improved LA class has the sail planes in the bow, bow planes that can be rigged in or out. This is an older LA class (688 to 725, Uss San Juan, SSN 751 started with the bow plane for underice capability).
Also, I do believe there is no difference between the lengths of a LA and Improved LA. Both are 360 feet, 8 inches long and 33 feet beam.
Also there is a conning tower, but it is not a tower anymore. The 'conn' is part of the control room. The sail (tower) is not manned during submerged operations. Only when the sub is on the surface are there men on the 'bridge', which is on top of the sail.
I served aboard one for 4 1/2 years!
Nice boat!!