If the Paper is embossed, then there is a strong possibility that an emulsion paint will not be happy, to both secure a lasting result and allow the emulsion to bond. Paint the paper with a thinned oil based undercoat prior to the emulsion.
That was a find!
I may have to defer to "TheDec's" superior familiairity with 20 year old embossed anaglyptas, but I am still struggling to believe that they will need oil painting before the application of emulsion paint.
Unless their surface is coated with some sort of plastic/polymer, they should be fine to paint with either matt or sillk emulsion.