I don't know if they are interchangeable, but I had to dissect my center vents once in an attempt to replace the bulb, and it requires a complete disassembly to free the louver that has the handle (which is molded on, not separate).

I would suspect that the chrome unit clips on anyway, so if MB offers it as a seperate part, you should be able to do the retrofit.

The newer MLs has the same chrome handles, and I toyed with the idea of upgrading my 99 louvers with the same deal...

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car