I have a grey market 280CE with 4speed stick trans. Are all the hydraulic clutch parts the same as a manual trans 240D of the same year? [1981]

My car has been in storage for a few years and the fluid reservoir which is shared with the brake master cylinder, has gone down. The brakes still work fine but the clutch just goes to the floor.

I have filled the reservoir but still no clutch activation. Any tips from folks that have had this problem? This happened once before and all I had to do was fill the reservoir. I've owned this car for 30 years.

Thanks for any help.