Are the factory original Platinum Spark Plugs marked differently than the replacement plugs installed every 60k miles?

I believe that I paid for spark plugs that were never installed, but I would appreciate help to prove that the little white "plus sign" on the terminal nut tips indicate factory originals.

My 2001 Camry LE is at 108k miles, I paid for Platinum Spark Plugs to be installed at my 60k mile service. When I had my regular 5k service at a different Toyota dealership, they told me the spark plugs need to be replaced because they are the originals. I went to another Toyota dealership for a second opinion and they confirmed the plugs are original. Since I now live in a different state from the dealership who completed the 60k mile service, I am dealing with this discrepancy by phone.

 

Are you stating the plugs were never changed at 60K miles, that the original plugs were left in the engine?

Per the shop manual the original plugs should be PK20TR11, double electrode platinum plug.

What are the spark plug part numbers for the ones the dealers state were in the engine?

Although these plugs last a long time! Guessing the dealers should be able to tell if a plug has 48K or 108K miles by the amount of electrode wear.

Denso has a website below. It may be possible to email customer service and ask your question about the marking.

http://www.densoproducts.com/default.asp?KID=26