Not necessary I must have been half asleep when I read your edit  it is perfectly clear and it was my reading that was blurry  Actually I believe that Boccherinis piano quintets preceded Dusseks httpimslporgwikiPianoQuintetsGOpBoccheriniLuigi But Boccherinis quintets and I am guessing Dusseks as well  I cant find a score for them are not anything like Schumanns There is no real interplay between the quartet and the keyboard which actually might have been a cembalo in Boccherinis thought the first violin doubling the right hand the cello the bass line almost throughout So I think it is fair to say that Schumann invented the form at least as we know it today