To determine whether the JES2 or JES3 exit interfaces are used, check any restarted job for the presence of U11-8xx type messages.
For the optional CA 11 JES2 Exit: Issue the "$DEXIT(6)" JES2 command. If module U11R22X6 is shown in the routines list and the exit is enabled, then the optional CA 11 JES2 exit, U11U2X, is used.
For optional CA 11 JES3 Exit: Issue the "*I X M=IATUX03" JES3 command. If the size is very small (around 00000040), then it is probably the default IBM exit. If the size is substantial, you will need to investigate whether the IATUX03 module is the optional CA 11 JES3 exit, U11U3X. One method is to look in the LNKLST for the first IATUX03 and browse it looking for "U11U3X".
As always, please contact CA Technologies support for CA Workload Restart Option for z/OS Scheduler if you have further questions.