If you want to eat the spaetzle directly, this is not necessary. Then just put the spaetzle in hot water and keep the spaetzle warm. However, if you want to serve the spaetzle later or store until the next day or fry it, then I recommend briefly rinsing the spaetzle with cold water. Otherwise, it may be that the Spaetzle stick together too much, thanks to the sticky gluten in the flour.