S1 Fulvia Seat options?

[GTVHarvin]

Hello all, new member and first post here.

I am considering purchasing an S1 1300 Coupe and wondering about seat options.

Do later series 2 and 3 or HF seats/seatrails also fit the S1 without modification ? (making it possible to have a headrest)

I searched older posts but haven't come up with any definitive answer so far.

[lancialulu]

Hf will not as different rails. Fulvia 3 will as will (rare) Sport version with headrest.

[GTVHarvin]

Thanks for the quick reply.
So then if I understand you correctly all Fulvia Coupe seat mountings are essentially interchangeable with the exception of HF?