Yes, side markers are the same for Kammbacks, SX/4s, and Spirits. Those used to be available through Kennedy American, but I haven't checked on that in awhile. There used to be a member on the Den that reproduced them for awhile, but I don't believe he is still active. His turned out really nice but they were just one color, without the silver on the raised portions of the lense. I don't know if you'll be able to do that or not.
Thanks!