I did check that as well... but couldn't find the answer I was looking for gearchange shift lever... Because 959 shows it but 899 doesn'tI was curious if the Ducati Comfort Seat for the 899 would fit the 959 so I went to look at the OEM parts diagram.
the 899 (https://amsducati.com/media/downloads/diagrams/ducati/2015-899.pdf) has the same part code for the seat as the 959 (https://amsducati.com/media/downloads/diagrams/ducati/2016-sbk959.pdf) so I assumed it's the same, interchangeable part.
I imagine you can follow this method if you are curious if a certain part is interchangeable.
Haven't tested my approach yet since I haven't had the time to install the seat. Will edit this post once I do.