My Tom Brown has no clip and comes with a sheath. The sheath has the Brown paw symbol on it. The clip was a later addition to the B15. At the time it came out, most WH knives were using a sheath instead of a clip. There is an article somewhere on the net that says the WH sheath system was a feature Brown liked, since he did not like clips.
IMHO, there are four things that make a WH Ti knife better than the competition. The steel is hard (ZDP), blade is thin and so is the edge (it is not a pry bar). The handles are scalloped inside so they are light. With the sheath, no clip, and rounded profile you get a very comfortable hande, much better than two slabs of Ti. The plunge lock is self adjusting and very reliable w/o any of the potential problems of a lockback, frame or liner lock.