Jeff, my springs are stamped perpendicular to the length of the spring (or parallel to the rear axle).
The car is a San Jose car assembled sometime between mid November to mid December, 1965.
It doesn't appear like my round spring inserts are unique as evantugby said his car had similar (only one per spring) inserts.
Thanks the marking would be consistent to what we see as a supplier for San Jose that year.
Yes but the finding the same detail does not automatically make the detail original. We see this all the time. If you both had Michelin tires we wouldn't accept them as being original to the car
His car was built at a different plant on the other side of the country and the plant was (for many parts) supplied from different suppliers. Since yours is San Jose I've likely seen tens of thousands of examples
Since these items often fall out or become worn it would not be unusual if the cars were serviced while being used as daily transportation for these to be replaced by a service station. I know we used to take them out of peoples cars and use them as Frisbee's around the service bays when we were kids
Kids do stupid things
Just thought of another thing. Did you find these at the loose spring or under the clamped leaf?
This might be the source of the difference since we don't see the clamped spring insulator (and I believe that is what you were referencing in the original post) as often as the unclamped
evantugby So you found only one version on your spring looking at the pictures your posted