Plonkers over pistons

Hi
I was talking to an old diesel guy today about nailing (pinking)
He said there is another thing to consider and that is the "plonkers." On some engines there is a pyramid type thing on the top of the piston on to which the injector sprays the fuel thus spreading the fuel evenly onto the top of the piston before ignition.
As I understood it my engine OM606 may not have these conical, pyramid things on the pistons. There could be a bar that sits directly under the injector nozzle onto which the diesel is sprayed thus dispersing the fuel evenly on the piston. Anyway he told me that in time these can burn or melt if things are not set up right and this can cause nailing. My question is does the OM606 have the pyramid things on the pistons or does it have “plonkers”

Cheers
Adrian