Are the internal parts of all w123 front seats cross compatible?

My 79 240d has collapsed springs and the foam has turned to dust. It feels like sitting on a chain link fence.

I have some seats out of a 83 or 84 240d that have a lot more spring and cushion to them, but they are the wrong color.

I can tell the style of the tex covering is different between the two, and the headrests are different, would the innards be movable from one to the other? Specifically the bottom part, but the back is pretty bad too.

Otherwise, maybe I should just get some foam cushion pads to put over them.

Thanks.

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