Not an answer but a rough guess:
Chapter 4 of the Robinson MM only states TBOs and SLLs of 2000 hours (or 12 years in some cases). Furthermore there is only one overhaul kit offered by the factory as all life limited parts time out at 2000 hours, unlike the R44 where the tailcone, some antenna mounts and the horizontal stabilizer have to be replaced in addition at 4400 hours.
Couldn't find anything about the SLLs of the RR300 but TBO should be the same as the airframe (2000 hours/3000 cycles).