in the past the 757 operating LAX-EWR on the 0800 and 1000 departures has been IPTE 752 basically day in and day out. not sure if this is still true as i have stopped flying the route regularly. the reverse flights EWR-LAX were the ~1530 and ~1700 departure times. they are 757-200 flights with UA flight numbers in the 1000-1499 range, IIRC.