When I recently purchased a 1987 300TD the PO included a set of later model leather front seats that he had wanted to swap into the car. I tried fitting them the other day and the bracket bolt holes are about an inch narrower on each side, i.e. for the front left bolt the bracket lands about an inch to right of the original bolt hole.

Other than that they look like later model leather w124 seats (I used to have 94 e320 wagon). One of the plugs is a bit different, I think due to them not having the memory function.

Anyone know what model they might have originally been from?