Yes, one of my childhood friends was at that dig because I tipped him off. He’s in one of the panning crowd shots in that movie. I’m aware of it.
Again, the urban legend was “millions of ET cartridges under six feet of cement.” Not a few boxes of broken crap. Which was how he characterized it.... and he was there....
Personally, I think it got conflated with the “thousands of unsold Atari Jaguar games in a cave story” which was also partially true.