Yes, the FTR model includes a PRS knob, which, when engaged, gives the user click stops at every 15˚ when panning; this is the designation 'R' in 'FTR'.
The 'F' refers to the Friction knob, and 'T' refers to the Tilt knob.
A 38FT is a 38mm ball head with both Friction knob and Tilt lock knob, and looks the same as an FTR head, but with one less knob (no 'R').
Load capacity is unchanged at 25kg (55lbs).
One more thing, the PRS knob ('R') can be added to an FT ball head by the end user at any time, if so desired; sold separately, a PRS knob retails for $60.
Thanks for asking; I hope my explanation wasn't too confusing, what with all the different features and designations.