Yep, in recent decades they switched from heroin to the production of synthetic drugs. Although they are still involved in heroin and to a lesser extent cocaine (one group operated in the Dutch Antilles).
Nearly three quarters of the first generation of Chinese who settled in the Netherlands in 1990 or earlier were born in Hong Kong or the neighboring province of Guandong. The rest come from the coastal province of Zhejiang, south of Shanghai. Chinese from other parts of China were unable to emigrate easily before 1990.