Thats right, but not the full picture.
R designates a restive supressor and Z an inductive resistor. You Need the Z in the right place though, If the Z is the first letter then its an extended gap plug, and if its the last letter it designates a 2.9mm electrode.
you need it in the middle! as in BP6ES,BPR6ES, and BPZ6ES being no supressor, resistive and inductive respectively.
If you get the Z in the wrong place the plug could potentially cause engine damage.
here the NGK chart so you can double check.