Course they bloody were!
Ultra Magnus G1: A blue and white car-carrier truck who shared a (cab) mold with Optimus Prime
Ultra Magnus RID(01): A blue and white car-carrier truck who was the the brother of Optimus Prime
Grimlock G1: Turns into a Tyrannosaurus and is leader of the Dinobots, who decides to work with the Autobots
Grimlock RID(15): Turns into a Tyrannosaurus who is a Dinobot and decides to work with the Autobots
What? All of these similarities with their G1 counterparts were just amazing coincidences?
If all they were doing was 'maintaining trademark' then why didn't they name the RID(01) Race Car 'Ultra Magnus' and the RID(01) Car Carrier Truck 'Mirage'?
Or name the red RID(15) car 'Grimlock' and the RID(15) dinosaur 'Sideswipe'?
Course they bloody took into account what namesakes the toys were based on! To think otherwise is ludicrous
That said, there are many examples that would fit your argument. Many times - too many times - they DO randomly use the old names to maintain trademark - like having an Orange Autobot Crane Truck in Armada named 'Smokescreen' for instance. Or a Machine Wars Blue Decepticon Fighter Jet named 'Megatron'.
So I don't discount your argument because in so many cases it would hold true - but I think the two examples you used don't stand up to scrutiny