D2 rear centre arm-rest through load

[eng33]

Still looking for a '02 D2 S8... When / if I eventually find a suitable car, one option I really want (which I had on my D2 '99 4.2 QS back in 2002) is a rear centre armrest that allows through load access, think it was called a 'ski bag'.

How common is this option on D2's? If a car doesn't have it, is it an easy mod, or would the complete rear seat require replacing?

Thanks!