Retrieving Initial LIBL from a Job in a JOBQ

I have found several ways of getting the library list of active jobs (API:
QUSRJOBI to name one).



I have found how to get the Job Description of a Job waiting in the JobQ.



But, I need to know how to get the "Initial Library" list of a job that is
waiting in the JoqQ (not actively running) as it may be different than the
library list of its associated job description.



Can anyone point me in the good direction to follow the rabbit down this
hole?



Thanks

Rich