C15 MBN serial number prefix ["bridge engine"] also has pilot injection; thus has a different camshaft (addt'l very small bump on injector lobe) and its own software.

It also has a "smart wastegate" to control turbo's wastegate function.

On MBNs; There might also have been a catalysis inside the OEM mufflers too; that a 6NZ didn't require. {6NZ emissions years were 2000-2002; but due to "Prebuy by the OEM truck manufacturers, you might have track chassis built in early 2003 , but still have a 6NZ engine, until they "ran out" of 6NZ inventory, at OEM truck factories}