The ProQ Emerald (Lifetechnology) is a covalent attachment of dye to the sugar residues on glycoproteins. So it may be suitable for your application. We also have Click-iT GalNAz metabolic glycoprotein labeling reagent (invitrogen) for labeling glycoproteins. Please provide more information about your application like how you want to use these probes?

Below reference provides the information about labeling of glycosylated protein.

Sialic Acids Attached to O-Glycans Modulate Voltage-gated Potassium Channel Gating.

J Biol Chem (2011) 286:4123-4132