Hi,
Since the thermostat is still basically new, you can reuse it. However, I would recommend replacing the gasket.
As far as the thermostat, it will likely be stuck to the engine, so it shouldn't fall, but it is possible.
When reinstalling, simply place the giggle valve at the specified location in the directions I sent on the original post. If you are concerned that it may fall or move, put a couple of small dabs of gasket maker on the thermostat outer ring, position it where you want it, and it will stick. Wait about 20 minutes for it to set before continuing.
Let me know if this helps.
Joe
Tuesday, November 9th, 2021 AT 8:48 PM