If this does not have to be for the past then you can record your IPLs using a rexx called IPLPARM or the something like that, IPLPARM can be found at
http://www.mzelden.com/mvsutil.htmlWe have a job that runs every day at 23:55 to document the IPL information.
//T EXEC PGM=IKJEFT1B,
// DYNAMNBR=35,
// REGION=512K,PARM='IPLPARM'
//SYSIN DD TERM=TS,SYSOUT=*
//SYSPRINT DD TERM=TS,SYSOUT=*
//SYSPROC DD DSN=SYNPU1.&SYSVNRN..CLIST,DISP=SHR
// DD DSN='SYNPU1.SYST.CLIST',DISP=SHR
//SYSTSPRT DD SYSOUT=*,DEST=(BASLERHG,LISTARCH)
//SYSTSIN DD DUMMY