Spark Plug Question??

[Rauder]

My GN has 42K miles, I bought it a month ago and it is hard starting when it sits for a few days and running a little rich. I checked the plugs and they are AC's but they have a "1" on the side of it. That is the only # on the plug, has anyone else came accross this type of plug? The plugs are clean not wet.

Thanks,
Ray