Why don't you post a link?
Here's a link to a couple of Chopin Nocturnes played on an 1836 Pleyel, which has all the typical features of a french piano soundboard: Parallel Stringing, reduced vibrating size of the soundboard and a tone-bar running parallel to the bridges.
the piano is in relatively good shape but it has the original dampers which have hardened on a couple of notes, therefore making a slight 'meow' or buzzy sound as the damper closes.. originally this would not have happened, as Pleyel dampers were very soft and had a long decay-time after the key was released..
..also, although the piano's hammers are in pretty good shape, the outer layer of the hammers would have been of a very soft and pliable leather which is almost impossible to find today, although in those days, because of the large use of leather for many applications, it was relatively easy for them to find very good oil-tanned leather.
one defect of oil tanning is that it turns rock-hard if it absorbs humidity, so even though many 'fortepiano' experts advocate keeping the original hammer-coverings the truth is that they should be replaced with a new layer of the appropriate leather..
so when you listen to these recordings try and imagine a softer attack and a rounder tone
Chopin was said to look for a glissando-like vocal quality to his scale passages, and he would not have liked how most antique 'fortepianos' have been restored today in my opinion
http://www.youtube.com/watch?v=hGmAeSuLPb0
