absolutely not, the robot enrichment stuff was added in an update and the assets for the fling trails all exist in the base 'portal2' folder, if it was from robot enrichment it would be in the 'update' folder.

Really? I feel like I remember it being a launch thing that got a bit of mockery around that time. (Justified tbh) and earliest patch notes seem to imply it was already in the game from the start. It remains a PC exclusive so if you played on console first you wouldn’t have seen it.