It would make a lot of sense to do this, better economically to recycle old trains than make new ones. Gwazi had 4 trains with 12 cars per train, 48 cars total. 16 of them went to InvadR (8 cars per train), and 24 will likely be going to Texas Stingray. Meaning that 8 trailered cars (no zero-cars left) are still unused, which I guess SeaWorld will either sell back to GCI to be refurbished for future projects for them, or they'll be used for parts for InvadR and Texas Stingray.
I posted my Sea World trip report yesterday and then forgot to share my Stingray photos here. A significant amount of the ride is built already and looks pretty good! I would not be surprised to see the structure completed by the end of the year, and it's starting to look like they'll be opening Stingray earlier rather than later. This project is becoming more and more exciting!
What isn't clear yet is how much of the ride in the backfield has been completed. They're currently building the crossover traversing the first valley as well as the bunny hills running out to the backfield, but it remains to be seen if the turns behind the lift have yet to be constructed.