the parts are available thru Isuzu still
the part numbers are:
PANEL; OUTER LWR,RR BODY - RIGHT 8-94450-408-0
PANEL; OUTER LWR,RR BODY - LEFT 8-94450-409-0
also i have a rather clean 90 Isuzu pup bed for 300.00. no rot, very little rust on the inside seams on the wheel housing , like MINOR.