Yes, the "R" indicates a resistor. Look at the NGK catalog.

Modern OE ignition systems don't generate more than about 35KV open circuit voltage. It only takes 5-10 KV to break down the gap resistance. Excessively high open circuit coil voltage just helps breakdown the secondary ignition components if there is an open circuit. What's important is ignition ENERGY (which usually measured in millijoules), and higher energy creates a longer duration spark, which is what is necessary to prevent misfires.

Modern OE igntion systems are HIGH ENERGY, not high voltage.

Advertised "coil voltage" is just marketing BS.

Duke