Yes, you can glue traditional PVC fittings onto PVC-Lock fittings.
PVC-lock fittings are made from a variation of ABS. While some PVC cements will work, we recommend using a cement for connecting ABS to PVC. All PVC-Lock fittings with a solvent weld interface shall meet ASTM standard D2466: Standard Specification for PVC Plastic Pipe Fittings, Schedule 40.
PVC-Lock fittings are designed to work with Class 200, Schedule 40, and Schedule 80 pipes.