83 70 Hp Evinrude spark plugs

[river rat]

I started to replacing the spark plugs on a 83 70 Hp Evinrude, I noticed a tag that said ONLY USE Champion L77J4 plugs.
When removing the old plugs out I noticed that the plugs were Champion
L77JC4 replacements.
Should I use L77JC4's or should I use a different plug?

[boats.net]

The C stands for copper plus design. You can use either one with no problems.