Non LHB version of BCT-ADI Duronto had AC-3 Economy coaches, thats why may be to increase pax load in LHB Duronto, some AC-3 new coaches with increased cap may be fitted.
In case of BDTS-NZM GR, it may be while to get new coaches becoz Rlys has not given new coaches to any GR yet..so rlys may or may not launch GR series with LHB avtaar,,
Humsafar is the new version of GRs