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I have not seen this plug here in the US, but R plugs are generally 'Radio Interference" plugs. And how they accomplish that is by adding Resistance to the plug.
Perhaps the new ones have some new tech that allows interference blockage without the resistance-- That would be nice.
Seeing that you have some of these and they are out of the engine, it would be interesting to do an Ohm reading from the tip to the electrode and see what you get , Do you have a meter???
The NGK page list there R plugs at 5K ohms.
Thanks ,
Arthur