Yes, the actors that smoke on set have to smoke herbal cigarettes.
In Coronation Street the actors who played Bet Lynch and Deidre Barlow hid their real cigarettes all over the set so as soon as filming stopped they could light up - even if that been smoking the fake fags for hours during filming.
With so many re-takes during filming actors can be smoking a lot and of course it is a workplace so nowadays the producers have a duty to protect everyone from secondary smoking, but herbal cigarettes were the norm long before this legislation