SUPVOL=NO means that a specific volume request is honored and the data set is not assigned to a pool.
So with CA Allocate you need to check the &ALLVOL variable for any volser passed from JCL.
The ALLVOL variable contains the list of volume serial numbers specified by the allocation requestor.
So the following ASR coding will be equivalent to SUPVOL=NO :
IF ... AND &ALLVOL NE '' THEN
... bypass setting the SG ... or set POOLSUB = 'N' ...