They meet in the very first episode. Their rivalry is established right then and there. And being a Supreme Commander, Galaxy Convoy would have known of Megatron by reputation.
How's that any different from the dub? Inferno, Ironhide, the first Wing Saber, Omega Supreme, Rodimus, Prowl, Bulkhead, Cliffjumper, Downshift, all the Omnicons, Superion Maximus, Snow Cat, and Demolishor are all still absent no matter how you slice it. At least Fun Pub wrote additional stories for the dub to account for a majority of these characters' absences from the cartoon.
Heck, you could even question Energon about most of the Armada cast's absence. Where was Red Alert during Energon before his sudden unexplained reappearance in Cybertron? What about Blurr, Scavenger, Side Swipe, Hoist, and Wheeljack? Scavenger was at least accounted for by a Fun Pub Cybertron story, but the rest were all never seen or heard from again. Why did none of them ever help out during the many crises that occurred throughout Energon? Energon/Superlink is no less guilty of this than Cybertron/Galaxy Force.
