The source for DQDECPR has not changed so the core mark does not need any change.
DQDECPR is assembled and link edited in the CA Datacom/DB new install job BDCUSNEW and upgrade install job BDCUSUPG into the CUSLIB. The reason to assemble onsite is that the customer’s latest CICS/TS modules from IBM are pulled into the assembly/link edit.
Also, no problems have been reported for DQDECPR. The last solution for it was with version 9.0 when CICS/TS originated necessitating a change. DQDECPR was moved from CAIMAC to CABDSAMP starting in 12.0 and thus the '12' source core mark update.
If a change is needed for DQDECPR in future, that would a reason to update the source core mark.