Alternatively you can use construction tugs instead of giving every module its own RCS and control system. I tend to do this even without KAS. Station bits are launched with no control systems unless they specificly need it for some reason. Launcher handles control until it reaches the proper orbit and the tug comes out to grab the part (launcher then deorbits). The tug is basicly RCS jets, mono prop tanks, Power and a probe core with lots of extra reaction wheels to deal with the off balanced thrust/COM its likely to have to deal with. At most this approach adds 1 docking port to the modules part count due to the tug needing a port to dock to in addition to the one that connects to the station although you could use a Klaw if that was really an issue.
With KAS like maverick said you could just send a kerbal out to pull off the RCS jets after the fact, just have the tanks wheels and prob core as a section that jettisoned after construction is complete.
