These amplifiers were sold as kits or as ready built units. The ready built units had serial numbers.
The most widely sold power amplifier was CS1500 which produced about 90W per channel into 8 Ohms and 140W per channel into 4 Ohms. There were also CS2000 mono blocks which were bridged versions of the CS1500.
The preamplifier was a CS1200M. The M stood for the incorporation of a moving coil pre-preamplifier stage. The preamp switched the mains supply to the power amp, which then sent the preamp power as low voltage via 2mm connectors at +/-15V.
They were reviewed here:- Crimson Elektrik 1200 series Pre/Power Amplifiers Lab Report | Hi-Fi News (hifinews.com)
The power amp in the review is not a CS1500 but is a similar kit. The CS1500 had the higher voltage taps in use (+/-45V DC) and the larger 250VA transformer.