Are the terms “PG 1159 star” and “pre-white dwarf” synonymous?

Are the terms "pre-white dwarf" (as in Gies et al. 2020, "Spectroscopic Detection of the Pre-White Dwarf Companion of Regulus") and "PG 1159 star" (as described, e.g. in Werner et al., 1996, named after the prototype object PG 1159-035) synonymous? I'm not entirely sure whether there are any pre-white dwarfs that are not PG 1159 stars, nor if there are any PG 1159 stars which are not pre-white dwarfs.