On just a brief look, probably ran across the same info that you already have, but here's what I came across:
P-47 42-23168 was a P-47D-RA-15, and P-38 42-68009 was a P-38J-10-LO.
Neither serial was listed in Joe Baugher's site at:
http://home.att.net/~jbaugher/usafserials.html
Might give these folks a try.
http://www.aerothentic.com/services/airplane_id.htm
http://www.aviationarchaeology.com/src/AFrptsMO.htm
Reference to other P-47s in the 43- serial range belonging to this unit is
also made at:
http://pagesperso-orange.fr/p-47.database/
Lots of wrecks at Lae and Nadzab #1
Late addition - From Pacific Wrecks website, this unit appears to be the 8th Service Group, 301st Aerodrome Squadron. Included in this Group was a Combat Replacement Training Center at Nadzab #1.