Not a "true LSD"???
LSD = limited-slip differential, NOT locking-differential. If 1200rc's setup prevents straight-line slip but doesn't lock up around corners, then it is LSD. There are various types of LSD, not just "one" type. Most are spring-loaded. Ford's current LSD is similiar to this in concept.
Be sure to read our last discussion of the Phantom Grip here:
Turn any diff to LSD!