An S Type is an S type. They all have the same under seat squab pressing & "floor" or lower rear seat support. I have 3 of massively varying age. The floors are all the same. The only change made on late cheapened cars was no more studs holding down carpets but the use of Velcro on cheaper carpet. Of course the Auto had a wider tunnel & no gearstick glass fibre dome & hole for stick (gear change lever).