I wonder if you heard New York giving flights heading northeast (oceanic) their next assigned primary and secondary HF frequencies and Gander was mentioned in those transmissions. Not at all unusual to hear (examples only) "At 44 and 1/2 north contact Gander Radio 8879 primary, 5649 secondary", or "Contact New York crossing <FIX>, frequency 8918 primary, 6585 secondary, Gander will be next". As a disclaimer though that wouldn't be typical on CAR-A or CAR-B, but more likely on NAT-A or NAT-E for hand-offs to either Gander or Santa Maria.