It's been known for quite a while that Adventure's egg wasn't the first (although Warshaw did get a lot of acknowledgement and visibility when his was believed to be the first, so it was good that we thought his was the first for a while). I think this is the third one found on the Channel F, all of which predate Adventure. Plus, somewhere in the middle, there was an arcade game named Starship 1 that also had an egg.