QUESTION: William Ridgway

I read in one of the Dummy Stamps newsletters available on the stampprintersinfo website that William Ridgway engraved the revenue stamps of Sarawak, as well as their early postage stamp issues, from 1869-71. Both printed by Maclure, MacDonald & Macgregor of London and Glasgow.

Seeing that the postage stamps were printed in litho, I'm wondering whether these revenue stamps were also printed in litho. Or were they maybe recess-printed? Does anyone have a Sarawak revenue catalogue or any of these revenue stamps at hand to check for me?

Cheers!
Adrian