That's what I am afraid too. I also have the older Aluminium GGTS. And because I have to leave a small distance between Iatty and cap for the airflow, the Iatty always moves a little. That couldn't be good for the threads. I hope the GGStealth will come soon and I can buy one of his caps. In the meantime I will order a 801to510 Adapter to use the Iatty with the 801-connector of my GGTS. It will look strange, but maybe it is better for the threads.
Do you have a TS with an overflow tank? If so I ordered a 510 to 901 and 901 to 510 adapters from madvapes. This fits perfectly I just threw in an 0 ring to block the small notched holes in the adapter. This keeps it tight and allows you to use the draw controll with the iAtty.