In the day, it was very common to rebuild coil spring pressure plates so all is not lost.

Have you contacted Sachs to see is the part is still in their system? They also might be able to recommend an alternate as it is common in the aftermarket to consolidate similar parts. Going with a higher torque capacity pressure plate may give you a stiffer clutch pedal so look at spring count / pressure.

There are many levels to NLA Not on the retailers shelf / not at the distribution warehouse the vendor buys from / not in the dealer parts network / not at the company that actually makes the part.