I looked up the spring option you mentioned, yes it looks like a really rare option also.
I find this car very confusing with the options it had, I would have to assume somebody special ordered it this way , but the combo is very confusing from the norm.
Also well taking things apart Ive noticed other strange things about it , that dont really add up, think it had a pretty storied life , looks like it was in two very bad wrecks.