The disc packs and 'cup compression washwers' are not dimensionally exactly the same as the earlier 901 ZF clucth-discs, but they will work. The early 901 ZF discs and compress-washers are NLA and those will eventually crack in half under torque pressure requiring immediate replacement.

Here is a good discussion thread on the subject http://www.914world.com/bbs2/index.php?showtopic=276703&st=0 along with a few other related topics.