Technical 1940's (?) Oldsmobile seat identification.

Not sure if this is the right place to post this but here goes...

I have a set of old seats, said to be out of a '40's oldsmobile or chev. Long story how I wound up with them but I don't really need them...before I can sell them I kinda need to know what they are.

Spring tags have the following numbers:

Rear bottom:

618
5833175

Rear back:

627
5834430

Front Bottom:

617
5833174

Front back - coils are covered so I can't find any numbers. I hope someone can point me in the right direction. Coils are black and still shiny!