I never heard that.
The GB4 are still the GB4 because there are more similarities among them than say, with Costilla, who was assumed to be a victim of Bittrolff's for which he was never charged up until Tierney dropped the charge on Rex, seemingly out of nowhere.
As for Taylor and Mack, they were each assumed to be killed by the same person for years. That person was not necessarily the Gilgo Beach killer. There is archive material that probably represents a lot of Trish's digital storage bill of heated debate about if the dismembering killer, often the "Manorville Butcher" was the same person as the Gilgo Beach killer, who was assumed to have killed the GB4.
Maureen has some differences, though. The time is different, the belt is different, the charge came at a different time, there was a troll-campaign to not bother charging on Maureen ("He's going away for life anyway, what's the difference?") the clarity of the location of Rex's family is different. I think the wrapping material might have been different, but I am not sure if I recall speculation or facts on the wrapping. It is different in that it is the case that got the most attention from Commissioner Hart, although she may not have had intended to connect the belt to Maureen.
MOO