Resurrecting this old thread to share a solution that I was able to find. Which is to use the Malaysian Airlines website. If you find your booking using your QF PNR, it will also show the LA PNR at the top of the page.
Hope this helps.
This holds true if your itinerary contains QF codeshares operated by LA flights within South America only as those codeshares are freesale codeshares and take from live LA inventory.
However, if it is the QF codeshare operated by LA on the transpacific, ie. QF3877/QF3876, these are blockspace codeshares and there is no LA record locator until 48-72h before departure depending on the carrier agreement.
The reason for this is because with blockspace codeshares, the codesharing carrier (QF in this case) has full management of the inventory for their set seat allocation until the flight goes to airport control. At this time, QF then sends the pax list to LA and that's when LA PNRs are created and therefore a LA record locator exists.
A word of warning if you have something like the following itinerary:
MEL QF SYD - QF prime flight
SYD QF*LA (QF3877) SCL -- a QF blockspace codeshare operated by LA
SCL QF*LA GRU -- a QF freesale codeshare operated by LA
GRU LA SCL - LA prime flight
SCL QF SYD - QF prime flight
SYD QF MEL - QF prime flight
In the above scenario, there will be a minimum of 5 record locators! If you booked via an agent that doesn't use Amadeus, there'll be 6 record locators.
1. QF's record locator that holds all 6 flights
2. LA's blockspace codeshare operating carrier record locator for the QF3877/LA800 SYD-SCL flight -- created 48-72h before departure
3. QF's freesale codeshare record locator in Sabre (that's the system LA uses) for the SCL-GRU codeshare
4. LA's freesale codeshare operating carrier record locator in Sabre for the SCL-GRU codeshare
5. LA's prime flight record locator for GRU-SCL
6. Agent record locator (if you booked via an agent that does not use Amadeus)