Yes.  The entire ETP bushing ID should have contact with the shaft and the hub should engage the full length of the ETP bushing sleeve OD (up to the flange of the bushing).  Additionally, the hub should have a sufficient thickness to properly mount to the ETP.  Shaft tolerance and the hub bore tolerance are also important for proper operation and torque transmission.  See the ETP catalog in the “Downloads” section of our web-site for details on proper hub sizing and dimensional/tolerance specifications for your particular size ETP.