You can use an MMC1/2/3/4/5 on your deck, the MMC20 CL is from an older series and won't fit.
Most cartridges in the MMC x range are shot, but can be repaired to like-new performance by Axel Schürholz at http://schallplattennadeln.de/
Beocenter 9300, Beogam CD50, Beocord 5500, Beomaster 3400, Beomaster 4400, 2 Beogram 4000, Beomaster 8000, 2 beogram 8002, Beovox S-75, Beovox MS150.2, Beovox RL6000, Beovox S-35, Beomaster 6000, 2 Beocord 9000, Beocord 8004, Beocord 5000, Form 1, 2x Beolink 1000, Beo4, MX3500, LS4500. Born 1993.