I picked up some parts for a tuneup and noticed that the distributor rotor has some sort of conductive coating on the end of it. I was bored so I took some pics. This is a factory Toyota Denso part, P/N 19102-61240. What is this mystery compound - some sort of conductive carbon cement? Does it serve as some sort of anti-fouling aid? I don't think I've seen this on other rotors found on domestics I've wrenched on in the past. Also, CDan or anyone, what does the date code stamped on the bottom translate to?