You see this one for sale a lot on the internet. I've bought good, high germination seeds of different kinds from this vendor who states up front that they don't know if the seeds will come true to type.
https://taste.ecrater.com/p/38...
Whirligig is said not to exhibit the "spoons" that make this cultivar appealing from saved seeds, so any place you source it keep that in mind. A plant you can multiply vegetatively might be a more certain option. Maybe someone who has tried growing out saved seeds will answer definitively.
Good luck.