My experience is with a 2004 SOHC engine and yes there are two.
The crank pos sensor is on the front of the engine, it is a stator ring mounted on the crankshaft pulley & balancer.
The cam sensor in the sohc on the back of the engine is a left over from the OHV, the SOHC has a "dummy" cam in the block where the OHV pushrod cam used to be, as far as we can figure it is there to drive the oil pump. The cam sensor is ONLY used during start up, at leas the one on the back of the engine is, I cannot say about the valve cover mounted sensor.
Maybe some SOHC experts will chime in here? I have only tuned up SOHC's and helped a friend stuff one in his 93 truck and wire it up...so details may be fuzzy, but I can tell you there are two cam sensors on the 04 block so I assume it never went away since 1994 when all 4.0L's got them