Would all depend on whether its original equipment of after-market.
If original equipment then I'd say there should be, best way to see for a VW system is that there is an electrical contact pad on the leading door pillar (about fuel filler height) and a matching set of sprung pins on the sliding door. Its about 3 inches by 1 inch.
If you don't have something similar then its unlikely that the slider has central locking.
Search through this forum section.....
About 2 months ago, someone had the same problem.
Found out the "plungers" for the door contact were in a right state.
Cleaned them and it worked, but he said he was gonna buy new anyway as they were so badly corroded.