I found one with the marking stamped on the large flat indicating that it had been repaired. I would love to know if this was done by a service center or a dealership or other type of central repair facility. See photo...

http://www.flickr.com/photos/bruckzone/8359429316/in/photostream/

Another look at the image

http://www.flickr.com/photos/bruckzone/8359381523/in/photostream

I imagine you could buy "refurbished" plugs at a discount. it wouldt surprise me if it was done at a service station or mechanic shop, shops used to have full plug maintenance centers that would clean gap and test them under pressure.

What a job, "spark plug repair technitian".

I was a spark plug repair technician in the 50's at my dad's service station. I was also the grease monkey, the wash boy, the chamois boy, the mechanic, and I polished and waxed a few cars. I also mopped the concrete drive and hosed it down. I worked 7 to 7, six days a week. I even pumped a little gas.

Ted, sounds like you were the Indispencibologist

No one, even those that are sure they are, is an "Indispencibologist".

Ted,

I had the same job as you had in 1975 at Gene Johnson's Gulf Station on Airport Blvd in Austin Texas. Only difference is that I did State Inspections most of the day and then mopped the concrete drive with kerosene and soap and then hosed it down. The darn station opened at 4:00 am and guess who opened it?

I bet you both can still smell that shop space now if you close your eyes even all these years later.

Did either of you have to mark the plugs as "repaired"?

Not I

Somewhere in the clouds of memory I remember seeing adverts for rebuilt or refurbished or reconditioned sparkplugs a long time ago.
It seems to me that it was in Popular Mechanics or Popular Science magazine.
Just can't put it all together right now.
Somebody must have been doing a lot of them at that time.